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Squid(プロキシサーバ、キャッシュサーバ)の設定方法(squid.confの書き方)

squid-2.5.STABLE3のデフォルトのsquid.confを使って各種設定方法を紹介します。
ネットワークに関する設定
連携サーバの選択アルゴリズムに関する設定
キャッシュサイズに関する設定
ログファイルのパスとキャッシュディレクトリ

squid-2.5.STABLE3のデフォルトのsquid.confを使って各種設定方法を紹介します。バージョンによって微妙に設定項目が違うかもしれませんが概ね同じでしょう。。。

#    WELCOME TO SQUID 2
#    ------------------
#
#    This is the default Squid configuration file. You may wish
#    to look at the Squid home page (http://www.squid-cache.org/)
#    for the FAQ and other documentation.
#
#    The default Squid config file shows what the defaults for
#    various options happen to be.  If you don't need to change the
#    default, you shouldn't uncomment the line.  Doing so may cause
#    run-time problems.  In some cases "none" refers to no default
#    setting at all, while in other cases it refers to a valid
#    option - the comments for that keyword indicate if this is the
#    case.
#


# NETWORK OPTIONS
# -----------------------------------------------------------------------------

■ ネットワークに関する設定


#  TAG: http_port
#    Usage:    port
#        hostname:port
#        1.2.3.4:port
#
#    The socket addresses where Squid will listen for HTTP client
#    requests.  You may specify multiple socket addresses.
#    There are three forms: port alone, hostname with port, and
#    IP address with port.  If you specify a hostname or IP
#    address, then Squid binds the socket to that specific
#    address.  This replaces the old 'tcp_incoming_address'
#    option.  Most likely, you do not need to bind to a specific
#    address, so you can use the port number alone.
#
#    The default port number is 3128.
#
#    If you are running Squid in accelerator mode, then you
#    probably want to listen on port 80 also, or instead.
#
#    The -a command line option will override the *first* port
#    number listed here.   That option will NOT override an IP
#    address, however.
#
#    You may specify multiple socket addresses on multiple lines.
#
#    If you run Squid on a dual-homed machine with an internal
#    and an external interface then we recommend you to specify the
#    internal address:port in http_port. This way Squid will only be
#    visible on the internal address.
#
#Default:
# http_port 3128
http_port 8080
squidが受け付けるhttpのポート番号。デフォルトは3128である。慣習的にproxyやcacheサーバのポート番号は8080や8000を利用することが多いので8080などに変えておく。squid
-a xxxx でsquidを起動した場合は起動オプションのxxxxポートが優先される。

#  TAG: https_port
# Note: This option is only available if Squid is rebuilt with the
#       --enable-ssl option
#
#        Usage:  [ip:]port cert=certificate.pem [key=key.pem] [options...]
#
#        The socket address where Squid will listen for HTTPS client
#        requests.
#
#        This is really only useful for situations where you are running
#        squid in accelerator mode and you want to do the SSL work at the
#        accelerator level.
#
#    You may specify multiple socket addresses on multiple lines,
#    each with their own SSL certificate and/or options.
#                 
#    Options:
#
#       cert=    Path to SSL certificate (PEM format)
#       
#       key=        Path to SSL private key file (PEM format)
#            if not specified, the certificate file is
#            assumed to be a combined certificate and
#            key file
#
#       version=    The version of SSL/TLS supported
#                1    automatic (default)
#                2    SSLv2 only
#                3    SSLv3 only
#                4    TLSv1 only
#
#       cipher=    Colon separated list of supported ciphers
#
#       options=    Varions SSL engine options. The most important
#            being:
#                NO_SSLv2  Disallow the use of SSLv2
#                NO_SSLv3  Disallow the use of SSLv3
#                NO_TLSv1  Disallow the use of TLSv1
#            See src/ssl_support.c or OpenSSL documentation
#            for a more complete list.
#
#Default:
# none
#  TAG: ssl_unclean_shutdown
# Note: This option is only available if Squid is rebuilt with the
#       --enable-ssl option
#
#    Some browsers (especially MSIE) bugs out on SSL shutdown
#    messages.
#
#Default:
# ssl_unclean_shutdown off

#  TAG: icp_port
#    The port number where Squid sends and receives ICP queries to
#    and from neighbor caches.  Default is 3130.  To disable use
#    "0".  May be overridden with -u on the command line.
#
#Default:
# icp_port 3130

複数のsquidサーバで、お互いのキャッシュ情報を参照し、効率的に連携させることができる。この参照作業で使われるプロトコルをICP(Internet
Cache Protocol)という。デフォルトでは3130番ポートを利用するように設定されている。この機能を無効にするには "0"を設定する。

#  TAG: htcp_port
# Note: This option is only available if Squid is rebuilt with the
#       --enable-htcp option
#
#    The port number where Squid sends and receives HTCP queries to
#    and from neighbor caches.  Default is 4827.  To disable use
#    "0".
#
#Default:
# htcp_port 4827

HTCP(Hyper Text Caching Protocol)を利用する場合のポート番号を設定する。デフォルトでは4827である。ただ、この機能を利用するには
configure実行時に --enable-htcp オプションを付けて実行しメイクしなければならない。既にインストールされているsquidの場合は
squid -v でsquidのバージョンとともにconfigure optionが表示されるので確認するとよい。

#  TAG: mcast_groups
#    This tag specifies a list of multicast groups which your server
#    should join to receive multicasted ICP queries.
#
#    NOTE!  Be very careful what you put here!  Be sure you
#    understand the difference between an ICP _query_ and an ICP
#    _reply_.  This option is to be set only if you want to RECEIVE
#    multicast queries.  Do NOT set this option to SEND multicast
#    ICP (use cache_peer for that).  ICP replies are always sent via
#    unicast, so this option does not affect whether or not you will
#    receive replies from multicast group members.
#
#    You must be very careful to NOT use a multicast address which
#    is already in use by another group of caches.
#
#    If you are unsure about multicast, please read the Multicast
#    chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
#
#    Usage: mcast_groups 239.128.16.128 224.0.1.20
#
#    By default, Squid doesn't listen on any multicast groups.
#
#Default:
# none

#  TAG: udp_incoming_address
#  TAG: udp_outgoing_address
#    udp_incoming_address    is used for the ICP socket receiving packets
#                from other caches.
#    udp_outgoing_address    is used for ICP packets sent out to other
#                caches.
#
#    The default behavior is to not bind to any specific address.
#
#    A udp_incoming_address value of 0.0.0.0 indicates that Squid should
#    listen for UDP messages on all available interfaces.
#
#    If udp_outgoing_address is set to 255.255.255.255 (the default)
#    then it will use the same socket as udp_incoming_address. Only
#    change this if you want to have ICP queries sent using another
#    address than where this Squid listens for ICP queries from other
#    caches.
#
#    NOTE, udp_incoming_address and udp_outgoing_address can not
#    have the same value since they both use port 3130.
#
#Default:
# udp_incoming_address 0.0.0.0
# udp_outgoing_address 255.255.255.255


# OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM

# -----------------------------------------------------------------------------

■ 連携サーバの選択アルゴリズムに関する設定


#  TAG: cache_peer
#    To specify other caches in a hierarchy, use the format:
#
#        cache_peer hostname type http_port icp_port
#
#    For example,
#
#    #                                        proxy  icp
#    #          hostname             type     port   port  options
#    #          -------------------- -------- ----- -----  -----------
#    cache_peer parent.foo.net       parent    3128  3130  [proxy-only]
#    cache_peer sib1.foo.net         sibling   3128  3130  [proxy-only]
#    cache_peer sib2.foo.net         sibling   3128  3130  [proxy-only]

複数のキャッシュサーバを連携させて動作させる場合に指定する。小規模なネットワークなどで単一のキャッシュサーバとして動作させる場合には設定の必要はない。
複数のSquidサーバを連携させる方法には parentsibling という大きく2つの方法がある。

parent で設定すると parent(親)になるSquidサーバに問い合わせを回送し、parentのSquidサーバからデータを受け取る仕組みになる。parentのSquidサーバは回送されたリクエストがキャッシュにヒット(HIT)すればそのデータを返し、ヒットしなかった場合には直接実際のサーバ(Webサーバなど)に実データを取りに行き、そのデータをリクエストがあったSquidサーバに転送する。

sibling で設定すると sibling(兄弟)となるSquidサーバに問い合わせを回送し、もしsiblingのSquidサーバのキャッシュにヒットしなかった場合(MISSの場合)は自ら実際のサーバ(Webサーバなど)に実データを取りに行く。

これら2つの設定をどのように使い分けるかというと、例えば、ファイアウォール(FireWall)をはさんで外部プロキシサーバと内部プロキシサーバが複数構築されているような一般的に環境を仮定してみる。

内部プロキシサーバは、通常直接インターネットとの通信を許可されていないので、直接インターネットとやり取りできる外部プロキシサーバを parent
に指定し、実際のデータ取得を外部プロキシサーバに委託する。

また、直接インターネットとやり取りできるプロキシサーバ複数を連携させるのであればそれぞれをsibling関係で設定し、キャッシュを有効利用することが可能になる。

このよう連携させることによってプロキシサーバ間の負荷分散はICPを用いることで実現できる。

またどちらの設定でもDNSラウンドロビンを使ってクライアントからの要求の負荷分散も実現できる。

#
#          type:  either 'parent', 'sibling', or 'multicast'.
#
#    proxy_port:  The port number where the cache listens for proxy
#             requests.
#
#      icp_port:  Used for querying neighbor caches about
#             objects.  To have a non-ICP neighbor
#             specify '7' for the ICP port and make sure the
#             neighbor machine has the UDP echo port
#             enabled in its /etc/inetd.conf file.
#
#        options: proxy-only
#             weight=n
#             ttl=n
#             no-query
#             default
#             round-robin
#             multicast-responder
#             closest-only
#             no-digest
#             no-netdb-exchange
#             no-delay
#             login=user:password | PASS | *:password
#             connect-timeout=nn
#             digest-url=url
#             allow-miss
#             max-conn
#
#             use 'proxy-only' to specify that objects fetched
#             from this cache should not be saved locally.
#
#             use 'weight=n' to specify a weighted parent.
#             The weight must be an integer.  The default weight
#             is 1, larger weights are favored more.
#
#             use 'ttl=n' to specify a IP multicast TTL to use
#             when sending an ICP queries to this address.
#             Only useful when sending to a multicast group.
#             Because we don't accept ICP replies from random
#             hosts, you must configure other group members as
#             peers with the 'multicast-responder' option below.
#
#             use 'no-query' to NOT send ICP queries to this
#             neighbor.
#
#             use 'default' if this is a parent cache which can
#             be used as a "last-resort." You should probably
#             only use 'default' in situations where you cannot
#             use ICP with your parent cache(s).
#
#             use 'round-robin' to define a set of parents which
#             should be used in a round-robin fashion in the
#             absence of any ICP queries.
#
#             'multicast-responder' indicates that the named peer
#             is a member of a multicast group.  ICP queries will
#             not be sent directly to the peer, but ICP replies
#             will be accepted from it.
#
#             'closest-only' indicates that, for ICP_OP_MISS
#             replies, we'll only forward CLOSEST_PARENT_MISSes
#             and never FIRST_PARENT_MISSes.
#
#             use 'no-digest' to NOT request cache digests from
#             this neighbor.
#
#             'no-netdb-exchange' disables requesting ICMP
#             RTT database (NetDB) from the neighbor.
#
#             use 'no-delay' to prevent access to this neighbor
#             from influencing the delay pools.
#
#             use 'login=user:password' if this is a personal/workgroup
#             proxy and your parent requires proxy authentication.
#             Note: The string can include URL escapes (i.e. %20 for
#             spaces). This also means that % must be written as %%.
#
#             use 'login=PASS' if users must authenticate against
#             the upstream proxy. This will pass the users credentials
#             as they are to the peer proxy. This only works for the
#             Basic HTTP authentication sheme. Note: To combine this
#             with proxy_auth both proxies must share the same user
#             database as HTTP only allows for one proxy login.
#             Also be warned that this will expose your users proxy
#             password to the peer. USE WITH CAUTION
#
#             use 'login=*:password' to pass the username to the
#             upstream cache, but with a fixed password. This is meant
#             to be used when the peer is in another administrative
#             domain, but it is still needed to identify each user.
#             The star can optionally be followed by some extra
#             information which is added to the username. This can
#             be used to identify this proxy to the peer, similar to
#             the login=username:password option above.
#
#             use 'connect-timeout=nn' to specify a peer
#             specific connect timeout (also see the
#             peer_connect_timeout directive)
#
#             use 'digest-url=url' to tell Squid to fetch the cache
#             digest (if digests are enabled) for this host from
#             the specified URL rather than the Squid default
#             location.
#
#             use 'allow-miss' to disable Squid's use of only-if-cached
#             when forwarding requests to siblings. This is primarily
#             useful when icp_hit_stale is used by the sibling. To
#             extensive use of this option may result in forwarding
#             loops, and you should avoid having two-way peerings
#             with this option. (for example to deny peer usage on
#             requests from peer by denying cache_peer_access if the
#             source is a peer)
#
#             use 'max-conn' to limit the amount of connections Squid
#             may open to this peer.
#
#    NOTE: non-ICP neighbors must be specified as 'parent'.
#
#Default:
# none

#  TAG: cache_peer_domain
#    Use to limit the domains for which a neighbor cache will be
#    queried.  Usage:
#
#    cache_peer_domain cache-host domain [domain ...]
#    cache_peer_domain cache-host !domain
#
#    For example, specifying
#
#        cache_peer_domain parent.foo.net    .edu

連携サーバへの問い合わせを特定のドメイン毎に限定する設定。上記の設定例では
.edu ドメインは parent.foo.net に問い合わせるようになる。また、!.edu のようにドメイン名の前に"!"記号を付加すると
.edu 以外のドメインというように否定形の設定も可能。

#
#    has the effect such that UDP query packets are sent to
#    'bigserver' only when the requested object exists on a
#    server in the .edu domain.  Prefixing the domainname
#    with '!' means that the cache will be queried for objects
#    NOT in that domain.
#
#    NOTE:    * Any number of domains may be given for a cache-host,
#          either on the same or separate lines.
#        * When multiple domains are given for a particular
#          cache-host, the first matched domain is applied.
#        * Cache hosts with no domain restrictions are queried
#          for all requests.
#        * There are no defaults.
#        * There is also a 'cache_peer_access' tag in the ACL
#          section.
#
#Default:
# none

#  TAG: neighbor_type_domain
#    usage: neighbor_type_domain parent|sibling domain domain ...
#
#    Modifying the neighbor type for specific domains is now
#    possible.  You can treat some domains differently than the the
#    default neighbor type specified on the 'cache_peer' line.
#    Normally it should only be necessary to list domains which
#    should be treated differently because the default neighbor type
#    applies for hostnames which do not match domains listed here.
#
#EXAMPLE:
#    cache_peer  parent cache.foo.org 3128 3130
#    neighbor_type_domain cache1.foo.org sibling .com .net
#    neighbor_type_domain cache2.foo.org parent .au .de

cache_peerで指定した連携サーバを特定のドメインへの問い合わせ時に変更する設定。上記の設定例では、.comと.netドメインはcache1.foo.orgにsiblingで問い合わせ、.auと.deドメインはcache2.foo.orgにparentで問い合わせる。

#
#Default:
# none

#  TAG: icp_query_timeout    (msec)
#    Normally Squid will automatically determine an optimal ICP
#    query timeout value based on the round-trip-time of recent ICP
#    queries.  If you want to override the value determined by
#    Squid, set this 'icp_query_timeout' to a non-zero value.  This
#    value is specified in MILLISECONDS, so, to use a 2-second
#    timeout (the old default), you would write:
#
#        icp_query_timeout 2000
#
#Default:
# icp_query_timeout 0

#  TAG: maximum_icp_query_timeout    (msec)
#    Normally the ICP query timeout is determined dynamically.  But
#    sometimes it can lead to very large values (say 5 seconds).
#    Use this option to put an upper limit on the dynamic timeout
#    value.  Do NOT use this option to always use a fixed (instead
#    of a dynamic) timeout value. To set a fixed timeout see the
#    'icp_query_timeout' directive.
#
#Default:
# maximum_icp_query_timeout 2000

#  TAG: mcast_icp_query_timeout    (msec)
#    For Multicast peers, Squid regularly sends out ICP "probes" to
#    count how many other peers are listening on the given multicast
#    address.  This value specifies how long Squid should wait to
#    count all the replies.  The default is 2000 msec, or 2
#    seconds.
#
#Default:
# mcast_icp_query_timeout 2000

#  TAG: dead_peer_timeout    (seconds)
#    This controls how long Squid waits to declare a peer cache
#    as "dead."  If there are no ICP replies received in this
#    amount of time, Squid will declare the peer dead and not
#    expect to receive any further ICP replies.  However, it
#    continues to send ICP queries, and will mark the peer as
#    alive upon receipt of the first subsequent ICP reply.
#
#    This timeout also affects when Squid expects to receive ICP
#    replies from peers.  If more than 'dead_peer' seconds have
#    passed since the last ICP reply was received, Squid will not
#    expect to receive an ICP reply on the next query.  Thus, if
#    your time between requests is greater than this timeout, you
#    will see a lot of requests sent DIRECT to origin servers
#    instead of to your parents.
#
#Default:
# dead_peer_timeout 10 seconds

#  TAG: hierarchy_stoplist
#    A list of words which, if found in a URL, cause the object to
#    be handled directly by this cache.  In other words, use this
#    to not query neighbor caches for certain objects.  You may
#    list this option multiple times.
#We recommend you to use at least the following line.
hierarchy_stoplist cgi-bin ?

URLにここで設定した文字列が含まれていた場合、他のサーバに問い合わせずに自分で取りに行く。デフォルトでは、"cgi-bin"または"?"が含まれるURLが対象になっている。

#  TAG: no_cache
#    A list of ACL elements which, if matched, cause the request to
#    not be satisfied from the cache and the reply to not be cached.
#    In other words, use this to force certain objects to never be cached.
#
#    You must use the word 'DENY' to indicate the ACL names which should
#    NOT be cached.
#
#We recommend you to use the following two lines.
acl QUERY urlpath_regex cgi-bin \?
no_cache deny QUERY

acl行でアクセス名QUERYは"cgi-bin"または"\?"を含むURLパスの正規表現と定義されている。no_cache
denyではアクセス名QUERYをキャッシュしない設定とする。


# OPTIONS WHICH AFFECT THE CACHE SIZE

# -----------------------------------------------------------------------------

■ キャッシュサイズに関する設定


#  TAG: cache_mem    (bytes)
#    NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
#    IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
#    USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
#    THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
#
#    'cache_mem' specifies the ideal amount of memory to be used
#    for:
#        * In-Transit objects
#        * Hot Objects
#        * Negative-Cached objects
#
#    Data for these objects are stored in 4 KB blocks.  This
#    parameter specifies the ideal upper limit on the total size of
#    4 KB blocks allocated.  In-Transit objects take the highest
#    priority.
#
#    In-transit objects have priority over the others.  When
#    additional space is needed for incoming data, negative-cached
#    and hot objects will be released.  In other words, the
#    negative-cached and hot objects will fill up any unused space
#    not needed for in-transit objects.
#
#    If circumstances require, this limit will be exceeded.
#    Specifically, if your incoming request rate requires more than
#    'cache_mem' of memory to hold in-transit objects, Squid will
#    exceed this limit to satisfy the new requests.  When the load
#    decreases, blocks will be freed until the high-water mark is
#    reached.  Thereafter, blocks will be used to store hot
#    objects.
#
#Default:
# cache_mem 8 MB
Squidはメモリをキャッシュ領域として利用する。そのための大きさを定義する。他のサービスを提供しないプロキシサーバのための専用マシンであればもっと大きくしても構わない。変更の際はコメントを外す。

#  TAG: cache_swap_low    (percent, 0-100)
#  TAG: cache_swap_high    (percent, 0-100)
#
#    The low- and high-water marks for cache object replacement.
#    Replacement begins when the swap (disk) usage is above the
#    low-water mark and attempts to maintain utilization near the
#    low-water mark.  As swap utilization gets close to high-water
#    mark object eviction becomes more aggressive.  If utilization is
#    close to the low-water mark less replacement is done each time.
#   
#    Defaults are 90% and 95%. If you have a large cache, 5% could be
#    hundreds of MB. If this is the case you may wish to set these
#    numbers closer together.
#
#Default:
# cache_swap_low 90
# cache_swap_high 95

cache_dirで設定したディスクキャッシュ容量に対して、空き容量を確保するための限界値を設定する。cache_swap_highで設定した容量(%)を超えると古いデータから削除され、cache_swap_lowで設定した容量(%)を下回ると削除を中止する。特に変更の必要はないと思われる。

#  TAG: maximum_object_size    (bytes)
#    Objects larger than this size will NOT be saved on disk.  The
#    value is specified in kilobytes, and the default is 4MB.  If
#    you wish to get a high BYTES hit ratio, you should probably
#    increase this (one 32 MB object hit counts for 3200 10KB
#    hits).  If you wish to increase speed more than your want to
#    save bandwidth you should leave this low.
#
#    NOTE: if using the LFUDA replacement policy you should increase
#    this value to maximize the byte hit rate improvement of LFUDA!
#    See replacement_policy below for a discussion of this policy.
#
#Default:
# maximum_object_size 4096 KB

ディスクキャッシュするデータサイズの上限値を定義する。デフォルトでは4096KBより大きいデータはキャッシュしない。必要に応じて大きくし、コメントを外す。

#  TAG: minimum_object_size    (bytes)
#    Objects smaller than this size will NOT be saved on disk.  The
#    value is specified in kilobytes, and the default is 0 KB, which
#    means there is no minimum.
#
#Default:
# minimum_object_size 0 KB

ディスクキャッシュするデータサイズの下限値を定義する。デフォルトでは0KBとなっており、これはmaximum_object_size
以下であれば全てキャッシュすることになる。1KBと設定すれば1KB未満のデータはキャッシュしなくなる。変更の必要はないと思われる。

#  TAG: maximum_object_size_in_memory    (bytes)
#        Objects greater than this size will not be attempted to kept in
#        the memory cache. This should be set high enough to keep objects
#        accessed frequently in memory to improve performance whilst low
#        enough to keep larger objects from hoarding cache_mem .
#
#Default:
# maximum_object_size_in_memory 8 KB

#  TAG: ipcache_size    (number of entries)
#  TAG: ipcache_low    (percent)
#  TAG: ipcache_high    (percent)
#    The size, low-, and high-water marks for the IP cache.
#
#Default:
# ipcache_size 1024
# ipcache_low 90
# ipcache_high 95

Squidは独自に名前解決を行うが、ipcache_sizeは名前解決した結果をメモリ上にキャッシュしておくアドレス数を指定する。また、ipcache_highで設定した上限値(%)に達すると古いデータからipcache_lowで設定した下限値(%)まで削除する。ipcache_sizeに関しては利用状況に応じて変更する。変更の際はコメントを外す。

#  TAG: fqdncache_size    (number of entries)
#    Maximum number of FQDN cache entries.
#
#Default:
# fqdncache_size 1024

ipcache_size同様にメモリ上にキャッシュしておくFQDNの最大エントリー数を指定する。必要に応じて変更し、コメントを外す。

#  TAG: cache_replacement_policy
#    The cache replacement policy parameter determines which
#    objects are evicted (replaced) when disk space is needed.
#
#        lru       : Squid's original list based LRU policy
#        heap GDSF : Greedy-Dual Size Frequency
#        heap LFUDA: Least Frequently Used with Dynamic Aging
#        heap LRU  : LRU policy implemented using a heap
#
#    Applies to any cache_dir lines listed below this.
#
#    The LRU policies keeps recently referenced objects.
#
#    The heap GDSF policy optimizes object hit rate by keeping smaller
#    popular objects in cache so it has a better chance of getting a
#    hit.  It achieves a lower byte hit rate than LFUDA though since
#    it evicts larger (possibly popular) objects.
#
#    The heap LFUDA policy keeps popular objects in cache regardless of
#    their size and thus optimizes byte hit rate at the expense of
#    hit rate since one large, popular object will prevent many
#    smaller, slightly less popular objects from being cached.
#
#    Both policies utilize a dynamic aging mechanism that prevents
#    cache pollution that can otherwise occur with frequency-based
#    replacement policies.
#
#    NOTE: if using the LFUDA replacement policy you should increase
#    the value of maximum_object_size above its default of 4096 KB to
#    to maximize the potential byte hit rate improvement of LFUDA.
#
#    For more information about the GDSF and LFUDA cache replacement
#    policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
#    and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
#
#Default:
# cache_replacement_policy lru

#  TAG: memory_replacement_policy
#    The memory replacement policy parameter determines which
#    objects are purged from memory when memory space is needed.
#
#    See cache_replacement_policy for details.
#
#Default:
# memory_replacement_policy lru


# LOGFILE PATHNAMES AND CACHE DIRECTORIES

# -----------------------------------------------------------------------------

■ ログファイルのパスとキャッシュディレクトリ


#  TAG: cache_dir
#    Usage:
#   
#    cache_dir Type Directory-Name Fs-specific-data [options]
#
#    cache_dir diskd Maxobjsize Directory-Name MB L1 L2 Q1 Q2
#
#    You can specify multiple cache_dir lines to spread the
#    cache among different disk partitions.
#
#    Type specifies the kind of storage system to use. Only "ufs"
#    is built by default. To eanble any of the other storage systems
#    see the --enable-storeio configure option.
#
#    'Directory' is a top-level directory where cache swap
#    files will be stored.  If you want to use an entire disk
#    for caching, then this can be the mount-point directory.
#    The directory must exist and be writable by the Squid
#    process.  Squid will NOT create this directory for you.
#
#    The ufs store type:
#
#    "ufs" is the old well-known Squid storage format that has always
#    been there.
#
#    cache_dir ufs Directory-Name Mbytes L1 L2 [options]
#
#    'Mbytes' is the amount of disk space (MB) to use under this
#    directory.  The default is 100 MB.  Change this to suit your
#    configuration.
#
#    'Level-1' is the number of first-level subdirectories which
#    will be created under the 'Directory'.  The default is 16.
#
#    'Level-2' is the number of second-level subdirectories which
#    will be created under each first-level directory.  The default
#    is 256.
#
#    The aufs store type:
#
#    "aufs" uses the same storage format as "ufs", utilizing
#    POSIX-threads to avoid blocking the main Squid process on
#    disk-I/O. This was formerly known in Squid as async-io.
#
#    cache_dir aufs Directory-Name Mbytes L1 L2 [options]
#
#    see argument descriptions under ufs above
#
#    The diskd store type:
#
#    "diskd" uses the same storage format as "ufs", utilizing a
#    separate process to avoid blocking the main Squid process on
#    disk-I/O.
#
#    cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
#
#    see argument descriptions under ufs above
#
#    Q1 specifies the number of unacknowledged I/O requests when Squid
#    stops opening new files. If this many messages are in the queues,
#    Squid won't open new files. Default is 64
#
#    Q2 specifies the number of unacknowledged messages when Squid
#    starts blocking.  If this many messages are in the queues,
#    Squid blocks until it recevies some replies. Default is 72
#
#    Common options:
#
#    read-only, this cache_dir is read only.
#
#    max-size=n, refers to the max object size this storedir supports.
#    It is used to initially choose the storedir to dump the object.
#    Note: To make optimal use of the max-size limits you should order
#    the cache_dir lines with the smallest max-size value first and the
#    ones with no max-size specification last.
#
#Default:
# cache_dir ufs /usr/local/squid/var/cache 100 16 256
cache_dirはディスクキャッシュのためのファイルシステム、ディレクトリ、容量、一次ディレクトリ数、二次ディレクトリ数を指定する。デフォルトのディスクキャッシュ容量は100MBになっているが、100GB程度のディスクが安価で手に入る現在では、ネットワークを流れるデータも膨大なものになっているため、ディスクキャッシュも数ギガバイト~数十ギガバイトあっても良いと思われる。大容量にキャッシュサーバにするのであればmaximum_object_sizeに関しても大きくした方が効率がよい。
一次ディレクトリ、二次ディレクトリはキャッシュ情報をインデックス化して管理するための格納場所になる。
一次ディレクトリ数16、二次ディレクトリ数256の意味は、/usr/local/squid/var/cache以下に00~0F(16進表記)の16個のディレクトリを作成(squid
-z で作成する)し、さらにそれぞれのディレクトリに00~FF(16進表記)の256個のディレクトリを作成して管理するということ。これに関しては特に変更の必要はないと思われる。

デフォルトでは上記で設定している/usr/local/squid/var/cacheディレクトリは存在しないので以下の作業を行う必要がある。

# cd /usr/local/squid/var
# mkdir cache
# chown nobody:nobody cache logs
 <-- ついでにログが管理されるlogsディレクトリのオーナーも変えておく
# /usr/local/squid/sbin/squid -z  <-- 一次ディレクトリ、二次ディレクトリが作成される
2003/06/18 02:16:19| Creating Swap Directories

#  TAG: cache_access_log
#    Logs the client request activity.  Contains an entry for
#    every HTTP and ICP queries received. To disable, enter "none".
#
#Default:
# cache_access_log /usr/local/squid/var/logs/access.log

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クライアントからのアクセス要求を記録するログファイルを指定する。上記がデフォルトの設定。特に変更の必要はない。

#  TAG: cache_log
#    Cache logging file. This is where general information about
#    your cache's behavior goes. You can increase the amount of data
#    logged to this file with the "debug_options" tag below.
#
#Default:
# cache_log /usr/local/squid/var/logs/cache.log

キャッシュの状況を記録するログファイルを指定する。特に変更の必要はない。

#  TAG: cache_store_log
#    Logs the activities of the storage manager.  Shows which
#    objects are ejected from the cache, and which objects are
#    saved and for how long.  To disable, enter "none". There are
#    not really utilities to analyze this data, so you can safely
#    disable it.
#
#Default:
# cache_store_log /usr/local/squid/var/logs/store.log

キャッシュの管理状況を記録するログファイルを指定する。特に変更の必要はない。

#  TAG: cache_swap_log
#    Location for the cache "swap.log."  This log file holds the
#    metadata of objects saved on disk.  It is used to rebuild the
#    cache during startup.  Normally this file resides in each
#    'cache_dir' directory, but you may specify an alternate
#    pathname here.  Note you must give a full filename, not just
#    a directory. Since this is the index for the whole object
#    list you CANNOT periodically rotate it!
#
#    If %s can be used in the file name then it will be replaced with a
#    a representation of the cache_dir name where each / is replaced
#    with '.'. This is needed to allow adding/removing cache_dir
#    lines when cache_swap_log is being used.
#   
#    If have more than one 'cache_dir', and %s is not used in the name
#    then these swap logs will have names such as:
#
#        cache_swap_log.00
#        cache_swap_log.01
#        cache_swap_log.02
#
#    The numbered extension (which is added automatically)
#    corresponds to the order of the 'cache_dir' lines in this
#    configuration file.  If you change the order of the 'cache_dir'
#    lines in this file, then these log files will NOT correspond to
#    the correct 'cache_dir' entry (unless you manually rename
#    them).  We recommend that you do NOT use this option.  It is
#    better to keep these log files in each 'cache_dir' directory.
#
#Default:
# none

#  TAG: emulate_httpd_log    on|off
#    The Cache can emulate the log file format which many 'httpd'
#    programs use.  To disable/enable this emulation, set
#    emulate_httpd_log to 'off' or 'on'.  The default
#    is to use the native log format since it includes useful
#    information that Squid-specific log analyzers use.
#
#Default:
# emulate_httpd_log off

http形式のログファイル形式で保存する場合にはonにする。デフォルトはoffで、Squid本来の形式で保存する。ログ管理ツールとの相性で変更する場合もある。

#  TAG: log_ip_on_direct    on|off
#    Log the destination IP address in the hierarchy log tag when going
#    direct. Earlier Squid versions logged the hostname here. If you
#    prefer the old way set this to off.
#
#Default:
# log_ip_on_direct on

#  TAG: mime_table
#    Pathname to Squid's MIME table. You shouldn't need to change
#    this, but the default file contains examples and formatting
#    information if you do.
#
#Default:
# mime_table /usr/local/squid/etc/mime.conf

#  TAG: log_mime_hdrs    on|off
#    The Cache can record both the request and the response MIME
#    headers for each HTTP transaction.  The headers are encoded
#    safely and will appear as two bracketed fields at the end of
#    the access log (for either the native or httpd-emulated log
#    formats).  To enable this logging set log_mime_hdrs to 'on'.
#
#Default:
# log_mime_hdrs off

#  TAG: useragent_log
# Note: This option is only available if Squid is rebuilt with the
#       --enable-useragent-log option
#
#    Squid will write the User-Agent field from HTTP requests
#    to the filename specified here.  By default useragent_log
#    is disabled.
#
#Default:
# none

HTTPリクエストに含まれるUser-Agentを記録するログファイルを指定する。User-Agentフィールドにはブラウザ名が含まれる。noneはUser-Agentログファイルを記録しない設定。デフォルトではこの機能を実装していないので利用する場合は、configure実行時に--enable-useragent_logオプションを付加し、コンパイルし直す必要がある。

#  TAG: referer_log
# Note: This option is only available if Squid is rebuilt with the
#       --enable-referer-log option
#
#    Squid will write the Referer field from HTTP requests to the
#    filename specified here.  By default referer_log is disabled.
#
#Default:
# none

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HTTPリクエストに含まれるRefererを記録するログファイルを指定する。Refererフィールドにはアクセスされたページを参照しているURL情報(アクセス元のサイトのURL)が含まれる。デフォルトでこの機能を実装していないので利用する場合は、configure実行時に--enable-referer-logオプションを付加し、コンパイルし直す必要がある。

#  TAG: pid_filename
#    A filename to write the process-id to.  To disable, enter "none".
#
#Default:
# pid_filename /usr/local/squid/var/logs/squid.pid

#  TAG: debug_options
#    Logging options are set as section,level where each source file
#    is assigned a unique section.  Lower levels result in less
#    output,  Full debugging (level 9) can result in a very large
#    log file, so be careful.  The magic word "ALL" sets debugging
#    levels for all sections.  We recommend normally running with
#    "ALL,1".
#
#Default:
# debug_options ALL,1

#  TAG: log_fqdn    on|off
#    Turn this on if you wish to log fully qualified domain names
#    in the access.log. To do this Squid does a DNS lookup of all
#    IP's connecting to it. This can (in some situations) increase
#    latency, which makes your cache seem slower for interactive
#    browsing.
#
#Default:
# log_fqdn off

#  TAG: client_netmask
#    A netmask for client addresses in logfiles and cachemgr output.
#    Change this to protect the privacy of your cache clients.
#    A netmask of 255.255.255.0 will log all IP's in that range with
#    the last digit set to '0'.
#
#Default:
# client_netmask 255.255.255.255


# OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
# -----------------------------------------------------------------------------

#  TAG: ftp_user
#    If you want the anonymous login password to be more informative
#    (and enable the use of picky ftp servers), set this to something
#    reasonable for your domain, like wwwuser@somewhere.net
#
#    The reason why this is domainless by default is that the
#    request can be made on the behalf of a user in any domain,
#    depending on how the cache is used.
#    Some ftp server also validate that the email address is valid
#    (for example perl.com).
#
#Default:
# ftp_user Squid@

#  TAG: ftp_list_width
#    Sets the width of ftp listings. This should be set to fit in
#    the width of a standard browser. Setting this too small
#    can cut off long filenames when browsing ftp sites.
#
#Default:
# ftp_list_width 32

#  TAG: ftp_passive
#    If your firewall does not allow Squid to use passive
#    connections, then turn off this option.
#
#Default:
# ftp_passive on

#  TAG: ftp_sanitycheck
#    For security and data integrity reasons Squid by default performs
#    sanity checks of the addresses of FTP data connections ensure the
#    data connection is to the requested server. If you need to allow
#    FTP connections to servers using another IP address for the data
#    connection then turn this off.
#
#Default:
# ftp_sanitycheck on

#  TAG: cache_dns_program
# Note: This option is only available if Squid is rebuilt with the
#       --disable-internal-dns option
#
#    Specify the location of the executable for dnslookup process.
#
#Default:
# cache_dns_program /usr/local/squid/libexec/

#  TAG: dns_children
# Note: This option is only available if Squid is rebuilt with the
#       --disable-internal-dns option
#
#    The number of processes spawn to service DNS name lookups.
#    For heavily loaded caches on large servers, you should
#    probably increase this value to at least 10.  The maximum
#    is 32.  The default is 5.
#
#    You must have at least one dnsserver process.
#
#Default:
# dns_children 5

#  TAG: dns_retransmit_interval
#    Initial retransmit interval for DNS queries. The interval is
#    doubled each time all configured DNS servers have been tried.
#
#
#Default:
# dns_retransmit_interval 5 seconds

#  TAG: dns_timeout
#    DNS Query timeout. If no response is received to a DNS query
#    within this time then all DNS servers for the queried domain
#    is assumed to be unavailable.
#
#Default:
# dns_timeout 5 minutes

#  TAG: dns_defnames    on|off
# Note: This option is only available if Squid is rebuilt with the
#       --disable-internal-dns option
#
#    Normally the 'dnsserver' disables the RES_DEFNAMES resolver
#    option (see res_init(3)).  This prevents caches in a hierarchy
#    from interpreting single-component hostnames locally.  To allow
#    dnsserver to handle single-component names, enable this
#    option.
#
#Default:
# dns_defnames off

#  TAG: dns_nameservers
#    Use this if you want to specify a list of DNS name servers
#    (IP addresses) to use instead of those given in your
#    /etc/resolv.conf file.
#    On Windows platforms, if no value is specified here or in
#    the /etc/resolv.conf file, the list of DNS name servers are
#    taken from the Windows registry, both static and dynamic DHCP
#    configurations are supported.
#
#    Example: dns_nameservers 10.0.0.1 192.172.0.4
#
#Default:
# none

#  TAG: hosts_file
#    Location of the host-local IP name-address associations
#    database.  Most Operating Systems have such a file: under
#    Un*X it's by default in /etc/hosts MS-Windows NT/2000 places
#    that in %SystemRoot%(by default
#    c:\winnt)\system32\drivers\etc\hosts, while Windows 9x/ME
#    places that in %windir%(usually c:\windows)\hosts
#
#    The file contains newline-separated definitions, in the
#    form ip_address_in_dotted_form name [name ...] names are
#    whitespace-separated.  lines beginnng with an hash (#)
#    character are comments.
#
#    The file is checked at startup and upon configuration.  If
#    set to 'none', it won't be checked.  If append_domain is
#    used, that domain will be added to domain-local (i.e. not
#    containing any dot character) host definitions.
#
#Default:
# hosts_file /etc/hosts

#  TAG: diskd_program
#    Specify the location of the diskd executable.
#    Note that this is only useful if you have compiled in
#    diskd as one of the store io modules.
#
#Default:
# diskd_program /usr/local/squid/libexec/

#  TAG: unlinkd_program
#    Specify the location of the executable for file deletion process.
#
#Default:
# unlinkd_program /usr/local/squid/libexec/unlinkd

#  TAG: pinger_program
# Note: This option is only available if Squid is rebuilt with the
#       --enable-icmp option
#
#    Specify the location of the executable for the pinger process.
#
#Default:
# pinger_program /usr/local/squid/libexec/

#  TAG: redirect_program
#    Specify the location of the executable for the URL redirector.
#    Since they can perform almost any function there isn't one included.
#    See the FAQ (section 15) for information on how to write one.
#    By default, a redirector is not used.
#
#Default:
# none

#  TAG: redirect_children
#    The number of redirector processes to spawn. If you start
#    too few Squid will have to wait for them to process a backlog of
#    URLs, slowing it down. If you start too many they will use RAM
#    and other system resources.
#
#Default:
# redirect_children 5

#  TAG: redirect_rewrites_host_header
#    By default Squid rewrites any Host: header in redirected
#    requests.  If you are running an accelerator then this may
#    not be a wanted effect of a redirector.
#
#Default:
# redirect_rewrites_host_header on

#  TAG: redirector_access
#    If defined, this access list specifies which requests are
#    sent to the redirector processes.  By default all requests
#    are sent.
#
#Default:
# none

#  TAG: auth_param
#    This is used to pass parameters to the various authentication
#    schemes.
#    format: auth_param scheme parameter [setting]
#   
#    auth_param basic program /usr/local/squid/bin/ncsa_auth /usr/local/squid/etc/passwd   

#    would tell the basic authentication scheme it's program parameter.
#
#    The order that authentication prompts are presented to the client_agent
#    is dependant on the order the scheme first appears in config file.
#    IE has a bug (it's not rfc 2617 compliant) in that it will use the basic
#    scheme if basic is the first entry presented, even if more secure schemes
#    are presented. For now use the order in the file below. If other browsers
#    have difficulties (don't recognise the schemes offered even if you are
using
#    basic) then either put basic first, or disable the other schemes (by
commenting
#    out their program entry).
#
#    Once an authentication scheme is fully configured, it can only be shutdown
#    by shutting squid down and restarting. Changes can be made on the fly
and
#    activated with a reconfigure. I.E. You can change to a different helper,
#    but not unconfigure the helper completely.
#
#    === Parameters for the basic scheme follow. ===
#   
#    "program" cmdline
#    Specify the command for the external authenticator.  Such a
#    program reads a line containing "username password" and replies
#    "OK" or "ERR" in an endless loop.  If you use an authenticator,
#    make sure you have 1 acl of type proxy_auth.  By default, the
#    authenticate_program is not used.
#
#    If you want to use the traditional proxy authentication,
#    jump over to the ../auth_modules/NCSA directory and
#    type:
#        % make
#        % make install
#
#    Then, set this line to something like
#
#    auth_param basic program /usr/local/squid/bin/ncsa_auth /usr/local/squid/etc/passwd
#
#    "children" numberofchildren
#    The number of authenticator processes to spawn (no default).
#    If you start too few Squid will have to wait for them to
#    process a backlog of usercode/password verifications, slowing
#    it down. When password verifications are done via a (slow)
#    network you are likely to need lots of authenticator
#    processes.
#    auth_param basic children 5
#
#    "realm" realmstring
#    Specifies the realm name which is to be reported to the
#    client for the basic proxy authentication scheme (part of
#    the text the user will see when prompted their username and
#    password). There is no default.
#    auth_param basic realm Squid proxy-caching web server
#
#    "credentialsttl" timetolive
#    Specifies how long squid assumes an externally validated
#    username:password pair is valid for - in other words how
#    often the helper program is called for that user. Set this
#    low to force revalidation with short lived passwords.  Note
#    that setting this high does not impact your susceptability
#    to replay attacks unless you are using an one-time password
#    system (such as SecureID).  If you are using such a system,
#    you will be vulnerable to replay attacks unless you also
#    enable the IP ttl is strict option.
#
#    === Parameters for the digest scheme follow ===
#
#    "program" cmdline
#    Specify the command for the external authenticator.  Such
#    a program reads a line containing "username":"realm" and
#    replies with the appropriate H(A1) value base64 encoded.
#    See rfc 2616 for the definition of H(A1).  If you use an
#    authenticator, make sure you have 1 acl of type proxy_auth.
#    By default, authentication is not used.
#
#    If you want to use build an authenticator,
#    jump over to the ../digest_auth_modules directory and choose the
#    authenticator to use. It it's directory type
#            % make
#            % make install
#
#    Then, set this line to something like
#
#    auth_param digest program /usr/local/squid/bin/digest_auth_pw /usr/local/squid/etc/digpass
#
#
#    "children" numberofchildren
#    The number of authenticator processes to spawn (no default).
#    If you start too few Squid will have to wait for them to
#    process a backlog of H(A1) calculations, slowing it down.
#    When the H(A1) calculations are done via a (slow) network
#    you are likely to need lots of authenticator processes.
#    auth_param digest children 5
#
#    "realm" realmstring
#    Specifies the realm name which is to be reported to the
#    client for the digest proxy authentication scheme (part of
#    the text the user will see when prompted their username and
#    password). There is no default.
#    auth_param digest realm Squid proxy-caching web server
#
#    "nonce_garbage_interval" timeinterval
#    Specifies the interval that nonces that have been issued
#    to client_agent's are checked for validity.
#
#    "nonce_max_duration" timeinterval
#    Specifies the maximum length of time a given nonce will be
#    valid for.
#
#    "nonce_max_count" number
#    Specifies the maximum number of times a given nonce can be
#    used.
#
#    "nonce_strictness" on|off
#    Determines if squid requires increment-by-1 behaviour for
#    nonce counts (on - the default), or strictly incrementing
#    (off - for use when useragents generate nonce counts that
#    occasionally miss 1 (ie, 1,2,4,6)).
#
#    === NTLM scheme options follow ===
#
#    "program" cmdline
#    Specify the command for the external ntlm authenticator.
#    Such a program reads a line containing the uuencoded NEGOTIATE
#    and replies with the ntlm CHALLENGE, then waits for the
#    response and answers with "OK" or "ERR" in an endless loop.
#    If you use an ntlm authenticator, make sure you have 1 acl
#    of type proxy_auth.  By default, the ntlm authenticator_program
#    is not used.
#
#    auth_param ntlm program /usr/local/squid/bin/ntlm_auth
#
#    "children" numberofchildren
#    The number of authenticator processes to spawn (no default).
#    If you start too few Squid will have to wait for them to
#    process a backlog of credential verifications, slowing it
#    down. When crendential verifications are done via a (slow)
#    network you are likely to need lots of authenticator
#    processes.
#    auth_param ntlm children 5
#
#    "max_challenge_reuses" number
#    The maximum number of times a challenge given by a ntlm
#    authentication helper can be reused. Increasing this number
#    increases your exposure to replay attacks on your network.
#    0 means use the challenge only once.  (disable challenge
#    caching) See max_ntlm_challenge_lifetime for more information.
#    auth_param ntlm max_challenge_reuses 0
#
#    "max_challenge_lifetime" timespan
#    The maximum time period that a ntlm challenge is reused
#    over.  The actual period will be the minimum of this time
#    AND the number of reused challenges.
#    auth_param ntlm max_challenge_lifetime 2 minutes
#
#Recommended minimum configuration:
#auth_param digest program <uncomment and complete this line>
#auth_param digest children 5
#auth_param digest realm Squid proxy-caching web server
#auth_param digest nonce_garbage_interval 5 minutes
#auth_param digest nonce_max_duration 30 minutes
#auth_param digest nonce_max_count 50
#auth_param ntlm program <uncomment and complete this line to activate>
#auth_param ntlm children 5
#auth_param ntlm max_challenge_reuses 0
#auth_param ntlm max_challenge_lifetime 2 minutes
#auth_param basic program <uncomment and complete this line>
auth_param basic children 5
auth_param basic realm Squid proxy-caching web server
auth_param basic credentialsttl 2 hours

#  TAG: authenticate_cache_garbage_interval
#    The time period between garbage collection across the
#    username cache.  This is a tradeoff between memory utilisation
#    (long intervals - say 2 days) and CPU (short intervals -
#    say 1 minute). Only change if you have good reason to.
#
#Default:
# authenticate_cache_garbage_interval 1 hour

#  TAG: authenticate_ttl
#    The time a user & their credentials stay in the logged in
#    user cache since their last request. When the garbage
#    interval passes, all user credentials that have passed their
#    TTL are removed from memory.
#
#Default:
# authenticate_ttl 1 hour

#  TAG: authenticate_ip_ttl
#    With this option you control how long a proxy authentication
#    will be bound to a specific IP address. If a request using
#    the same user name is received during this time then access
#    will be denied and both users are required to reauthenticate
#    them selves.  The idea behind this is to make it annoying
#    for people to share their password to their friends, but
#    yet allow a dialup user to reconnect on a different dialup
#    port.
#
#    The default is 0 to disable the check. Recommended value
#    if you have dialup users are no more than 60 seconds to allow
#    the user to redial without hassle. If all your users are
#    stationary then higher values may be used.
#
#    See also the acl max_user_ip. The max_user_ip acl replaces
#    the authenticate_ip_ttl_is_strict option found in earlier
#    Squid versions.
#
#Default:
# authenticate_ip_ttl 0 seconds

#  TAG: external_acl_type
#    This option defines external acl classes using a helper program
#    to look up the status
#   
#      external_acl_type name [options] FORMAT.. /path/to/helper [helper
arguments..]
#   
#    Options:
#
#      ttl=n        TTL in seconds for cached results (defaults to 3600
#              for 1 hour)
#      negative_ttl=n
#              TTL for cached negative lookups (default same
#              as ttl)
#      concurrency=n    Concurrency level / number of processes spawn
#            to service external acl lookups of this type.
#      cache=n    result cache size, 0 is unbounded (default)
#   
#    FORMAT specifications
#
#      %LOGIN    Authenticated user login name
#      %IDENT    Ident user name
#      %SRC        Client IP
#      %DST        Requested host
#      %PROTO    Requested protocol
#      %PORT        Requested port
#      %METHOD    Request method
#      %{Header}    HTTP request header
#      %{Hdr:member}    HTTP request header list member
#      %{Hdr:;member}
#              HTTP request header list member using ; as
#              list separator. ; can be any non-alphanumeric
#            character.
#
#    In addition, any string specified in the referencing acl will
#    also be included in the helper request line, after the specified
#    formats (see the "acl external" directive)
#
#    The helper receives lines per the above format specification,
#    and returns lines starting with OK or ERR indicating the validity
#    of the request and optionally followed by additional keywords with
#    more details.
#
#    General result syntax:
#   
#      OK/ERR keyword=value ...
#
#    Defined keywords:
#
#      user=        The users name (login)
#      error=    Error description (only defined for ERR results)
#
#    Keyword values need to be enclosed in quotes if they may contain
#    whitespace, or the whitespace escaped using \. Any quotes or \
#    characters within the keyword value must be \ escaped.
#
#Default:
# none


# OPTIONS FOR TUNING THE CACHE
# -----------------------------------------------------------------------------

#  TAG: wais_relay_host
#  TAG: wais_relay_port
#    Relay WAIS request to host (1st arg) at port (2 arg).
#
#Default:
# wais_relay_port 0

#  TAG: request_header_max_size    (KB)
#    This specifies the maximum size for HTTP headers in a request.
#    Request headers are usually relatively small (about 512 bytes).
#    Placing a limit on the request header size will catch certain
#    bugs (for example with persistent connections) and possibly
#    buffer-overflow or denial-of-service attacks.
#
#Default:
# request_header_max_size 10 KB

#  TAG: request_body_max_size    (KB)
#    This specifies the maximum size for an HTTP request body.
#    In other words, the maximum size of a PUT/POST request.
#    A user who attempts to send a request with a body larger
#    than this limit receives an "Invalid Request" error message.
#    If you set this parameter to a zero (the default), there will
#    be no limit imposed.
#
#Default:
# request_body_max_size 0 KB

#  TAG: refresh_pattern
#    usage: refresh_pattern [-i] regex min percent max [options]
#
#    By default, regular expressions are CASE-SENSITIVE.  To make
#    them case-insensitive, use the -i option.
#
#    'Min' is the time (in minutes) an object without an explicit
#    expiry time should be considered fresh. The recommended
#    value is 0, any higher values may cause dynamic applications
#    to be erroneously cached unless the application designer
#    has taken the appropriate actions.
#
#    'Percent' is a percentage of the objects age (time since last
#    modification age) an object without explicit expiry time
#    will be considered fresh.
#
#    'Max' is an upper limit on how long objects without an explicit
#    expiry time will be considered fresh.
#
#    options: override-expire
#         override-lastmod
#         reload-into-ims
#         ignore-reload
#
#        override-expire enforces min age even if the server
#        sent a Expires: header. Doing this VIOLATES the HTTP
#        standard.  Enabling this feature could make you liable
#        for problems which it causes.
#
#        override-lastmod enforces min age even on objects
#        that was modified recently.
#
#        reload-into-ims changes client no-cache or ``reload''
#        to If-Modified-Since requests. Doing this VIOLATES the
#        HTTP standard. Enabling this feature could make you
#        liable for problems which it causes.
#
#        ignore-reload ignores a client no-cache or ``reload''
#        header. Doing this VIOLATES the HTTP standard. Enabling
#        this feature could make you liable for problems which
#        it causes.
#       
#    Please see the file doc/Release-Notes-1.1.txt for a full
#    description of Squid's refresh algorithm.  Basically a
#    cached object is: (the order is changed from 1.1.X)
#
#        FRESH if expires < now, else STALE
#        STALE if age > max
#        FRESH if lm-factor < percent, else STALE
#        FRESH if age < min
#        else STALE
#
#    The refresh_pattern lines are checked in the order listed here.
#    The first entry which matches is used.  If none of the entries
#    match, then the default will be used.
#
#    Note, you must uncomment all the default lines if you want
#    to change one. The default setting is only active if none is
#    used.
#
#Suggested default:
refresh_pattern ^ftp:        1440    20%    10080
refresh_pattern ^gopher:    1440    0%    1440
refresh_pattern .        0    20%    4320

#  TAG: quick_abort_min    (KB)
#  TAG: quick_abort_max    (KB)
#  TAG: quick_abort_pct    (percent)
#    The cache by default continues downloading aborted requests
#    which are almost completed (less than 16 KB remaining). This
#    may be undesirable on slow (e.g. SLIP) links and/or very busy
#    caches.  Impatient users may tie up file descriptors and
#    bandwidth by repeatedly requesting and immediately aborting
#    downloads.
#
#    When the user aborts a request, Squid will check the
#    quick_abort values to the amount of data transfered until
#    then.
#
#    If the transfer has less than 'quick_abort_min' KB remaining,
#    it will finish the retrieval.
#
#    If the transfer has more than 'quick_abort_max' KB remaining,
#    it will abort the retrieval.
#
#    If more than 'quick_abort_pct' of the transfer has completed,
#    it will finish the retrieval.
#
#    If you do not want any retrieval to continue after the client
#    has aborted, set both 'quick_abort_min' and 'quick_abort_max'
#    to '0 KB'.
#
#    If you want retrievals to always continue if they are being
#    cached then set 'quick_abort_min' to '-1 KB'.
#
#Default:
# quick_abort_min 16 KB
# quick_abort_max 16 KB
# quick_abort_pct 95

#  TAG: negative_ttl    time-units
#    Time-to-Live (TTL) for failed requests.  Certain types of
#    failures (such as "connection refused" and "404 Not Found") are
#    negatively-cached for a configurable amount of time.  The
#    default is 5 minutes.  Note that this is different from
#    negative caching of DNS lookups.
#
#Default:
# negative_ttl 5 minutes

#  TAG: positive_dns_ttl    time-units
#    Time-to-Live (TTL) for positive caching of successful DNS lookups.
#    Default is 6 hours (360 minutes).  If you want to minimize the
#    use of Squid's ipcache, set this to 1, not 0.
#
#Default:
# positive_dns_ttl 6 hours

#  TAG: negative_dns_ttl    time-units
#    Time-to-Live (TTL) for negative caching of failed DNS lookups.
#
#Default:
# negative_dns_ttl 5 minutes

#  TAG: range_offset_limit    (bytes)
#    Sets a upper limit on how far into the the file a Range request
#    may be to cause Squid to prefetch the whole file. If beyond this
#    limit then Squid forwards the Range request as it is and the result
#    is NOT cached.
#
#    This is to stop a far ahead range request (lets say start at 17MB)
#    from making Squid fetch the whole object up to that point before
#    sending anything to the client.
#
#    A value of -1 causes Squid to always fetch the object from the
#    beginning so that it may cache the result. (2.0 style)
#
#    A value of 0 causes Squid to never fetch more than the
#    client requested. (default)
#
#Default:
# range_offset_limit 0 KB


# TIMEOUTS
# -----------------------------------------------------------------------------

#  TAG: connect_timeout    time-units
#    Some systems (notably Linux) can not be relied upon to properly
#    time out connect(2) requests.  Therefore the Squid process
#    enforces its own timeout on server connections.  This parameter
#    specifies how long to wait for the connect to complete.  The
#    default is two minutes (120 seconds).
#
#Default:
# connect_timeout 2 minutes

#  TAG: peer_connect_timeout    time-units
#    This parameter specifies how long to wait for a pending TCP
#    connection to a peer cache.  The default is 30 seconds.   You
#    may also set different timeout values for individual neighbors
#    with the 'connect-timeout' option on a 'cache_peer' line.
#
#Default:
# peer_connect_timeout 30 seconds

#  TAG: read_timeout    time-units
#    The read_timeout is applied on server-side connections.  After
#    each successful read(), the timeout will be extended by this
#    amount.  If no data is read again after this amount of time,
#    the request is aborted and logged with ERR_READ_TIMEOUT.  The
#    default is 15 minutes.
#
#Default:
# read_timeout 15 minutes

#  TAG: request_timeout
#    How long to wait for an HTTP request after initial
#    connection establishment.
#
#Default:
# request_timeout 5 minutes

#  TAG: persistent_request_timeout
#    How long to wait for the next HTTP request on a persistent
#    connection after the previous request completes.
#
#Default:
# persistent_request_timeout 1 minute

#  TAG: client_lifetime    time-units
#    The maximum amount of time that a client (browser) is allowed to
#    remain connected to the cache process.  This protects the Cache
#    from having a lot of sockets (and hence file descriptors) tied up
#    in a CLOSE_WAIT state from remote clients that go away without
#    properly shutting down (either because of a network failure or
#    because of a poor client implementation).  The default is one
#    day, 1440 minutes.
#
#    NOTE:  The default value is intended to be much larger than any
#    client would ever need to be connected to your cache.  You
#    should probably change client_lifetime only as a last resort.
#    If you seem to have many client connections tying up
#    filedescriptors, we recommend first tuning the read_timeout,
#    request_timeout, persistent_request_timeout and quick_abort values.
#
#Default:
# client_lifetime 1 day

#  TAG: half_closed_clients
#    Some clients may shutdown the sending side of their TCP
#    connections, while leaving their receiving sides open.    Sometimes,
#    Squid can not tell the difference between a half-closed and a
#    fully-closed TCP connection.  By default, half-closed client
#    connections are kept open until a read(2) or write(2) on the
#    socket returns an error.  Change this option to 'off' and Squid
#    will immediately close client connections when read(2) returns
#    "no more data to read."
#
#Default:
# half_closed_clients on

#  TAG: pconn_timeout
#    Timeout for idle persistent connections to servers and other
#    proxies.
#
#Default:
# pconn_timeout 120 seconds

#  TAG: ident_timeout
#    Maximum time to wait for IDENT lookups to complete.
#   
#    If this is too high, and you enabled IDENT lookups from untrusted
#    users, then you might be susceptible to denial-of-service by having
#    many ident requests going at once.
#
#Default:
# ident_timeout 10 seconds

#  TAG: shutdown_lifetime    time-units
#    When SIGTERM or SIGHUP is received, the cache is put into
#    "shutdown pending" mode until all active sockets are closed.
#    This value is the lifetime to set for all open descriptors
#    during shutdown mode.  Any active clients after this many
#    seconds will receive a 'timeout' message.
#
#Default:
# shutdown_lifetime 30 seconds


# ACCESS CONTROLS
# -----------------------------------------------------------------------------

#  TAG: acl
#    Defining an Access List
#
#    acl aclname acltype string1 ...
#    acl aclname acltype "file" ...
#
#    when using "file", the file should contain one item per line
#
#    acltype is one of the types described below
#
#    By default, regular expressions are CASE-SENSITIVE.  To make
#    them case-insensitive, use the -i option.
#
#    acl aclname src      ip-address/netmask ... (clients IP address)
#    acl aclname src      addr1-addr2/netmask ... (range of addresses)
#    acl aclname dst      ip-address/netmask ... (URL host's IP address)
#    acl aclname myip     ip-address/netmask ... (local socket IP address)
#
#    acl aclname srcdomain   .foo.com ...    # reverse lookup, client IP
#    acl aclname dstdomain   .foo.com ...    # Destination server from URL
#    acl aclname srcdom_regex [-i] xxx ...   # regex matching client name
#    acl aclname dstdom_regex [-i] xxx ...   # regex matching server
#      # For dstdomain and dstdom_regex  a reverse lookup is tried if a IP
#      # based URL is used. The name "none" is used if the reverse lookup
#      # fails.
#
#    acl aclname time     [day-abbrevs]  [h1:m1-h2:m2]
#        day-abbrevs:
#        S - Sunday
#        M - Monday
#        T - Tuesday
#        W - Wednesday
#        H - Thursday
#        F - Friday
#        A - Saturday
#        h1:m1 must be less than h2:m2
#    acl aclname url_regex [-i] ^http:// ...    # regex matching on whole
URL
#    acl aclname urlpath_regex [-i] \.gif$ ...    # regex matching on URL
path
#    acl aclname port     80 70 21 ...
#    acl aclname port     0-1024 ...        # ranges allowed
#    acl aclname myport   3128 ...        # (local socket TCP port)
#    acl aclname proto    HTTP FTP ...
#    acl aclname method   GET POST ...
#    acl aclname browser  [-i] regexp ...
#      # pattern match on User-Agent header
#        acl aclname referer_regex  [-i] regexp ...
#          # pattern match on Referer header
#          # Referer is highly unreliable, so use with care
#    acl aclname ident    username ...
#    acl aclname ident_regex [-i] pattern ...
#      # string match on ident output.
#      # use REQUIRED to accept any non-null ident.
#    acl aclname src_as   number ...
#    acl aclname dst_as   number ...
#      # Except for access control, AS numbers can be used for
#      # routing of requests to specific caches. Here's an
#      # example for routing all requests for AS#1241 and only
#      # those to mycache.mydomain.net:
#      # acl asexample dst_as 1241
#      # cache_peer_access mycache.mydomain.net allow asexample
#      # cache_peer_access mycache_mydomain.net deny all
#
#    acl aclname proxy_auth username ...
#    acl aclname proxy_auth_regex [-i] pattern ...
#      # list of valid usernames
#      # use REQUIRED to accept any valid username.
#      #
#      # NOTE: when a Proxy-Authentication header is sent but it is not
#      # needed during ACL checking the username is NOT logged
#      # in access.log.
#      #
#      # NOTE: proxy_auth requires a EXTERNAL authentication program
#      # to check username/password combinations (see
#      # authenticate_program).
#      #
#      # WARNING: proxy_auth can't be used in a transparent proxy. It
#      # collides with any authentication done by origin servers. It may
#      # seem like it works at first, but it doesn't.
#
#    acl aclname snmp_community string ...
#      # A community string to limit access to your SNMP Agent
#      # Example:
#      #
#      #    acl snmppublic snmp_community public
#
#    acl aclname maxconn number
#      # This will be matched when the client's IP address has
#      # more than <number> HTTP connections established.
#
#    acl aclname max_user_ip [-s] number
#      # This will be matched when the user attempts to log in from more
#      # than <number> different ip address's. The authenticate_ip_ttl
#      # parameter controls the timeout on the ip entries.
#      # If -s is specified then the limit is strict, denying browsing
#      # from any further IP addresses until the ttl has expired. Without
#      # -s Squid will just annoy the user by "randomly" deny requests.
#      # (the counter is then reset each time the limit is reached and a
#      # request is denied)
#      # NOTE: in acceleration mode or where there is mesh of child proxies,
#      # clients may appear to come from multiple address's if they are
#      # going through proxy farms, so a limit of 1 may cause user problems.
#
#    acl aclname req_mime_type mime-type1 ...
#      # regex match agains the mime type of the request generated
#      # by the client. Can be used to detect file upload or some
#      # types HTTP tunelling requests.
#      # NOTE: This does NOT match the reply. You cannot use this
#      # to match the returned file type.
#
#    acl aclname rep_mime_type mime-type1 ...
#      # regex match against the mime type of the reply recieved by
#      # squid. Can be used to detect file download or some
#      # types HTTP tunelling requests.
#      # NOTE: This has no effect in http_access rules. It only has
#      # effect in rules that affect the reply data stream such as
#      # http_reply_access.
#
#    acl acl_name external class_name [arguments...]
#      # external ACL lookup via a helper class defined by the
#      # external_acl_type directive.
#
#Examples:
#acl myexample dst_as 1241
#acl password proxy_auth REQUIRED
#acl fileupload req_mime_type -i ^multipart/form-data$
#acl javascript rep_mime_type -i ^application/x-javascript$
#
#Recommended minimum configuration:
acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
acl SSL_ports port 443 563
acl Safe_ports port 80        # http
acl Safe_ports port 21        # ftp
acl Safe_ports port 443 563    # https, snews
acl Safe_ports port 70        # gopher
acl Safe_ports port 210        # wais
acl Safe_ports port 1025-65535    # unregistered ports
acl Safe_ports port 280        # http-mgmt
acl Safe_ports port 488        # gss-http
acl Safe_ports port 591        # filemaker
acl Safe_ports port 777        # multiling http
acl CONNECT method CONNECT

#  TAG: http_access
#    Allowing or Denying access based on defined access lists
#
#    Access to the HTTP port:
#    http_access allow|deny [!]aclname ...
#
#    NOTE on default values:
#
#    If there are no "access" lines present, the default is to deny
#    the request.
#
#    If none of the "access" lines cause a match, the default is the
#    opposite of the last line in the list.  If the last line was
#    deny, then the default is allow.  Conversely, if the last line
#    is allow, the default will be deny.  For these reasons, it is a
#    good idea to have an "deny all" or "allow all" entry at the end
#    of your access lists to avoid potential confusion.
#
#Default:
# http_access deny all
#
#Recommended minimum configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
http_access deny manager
# Deny requests to unknown ports
http_access deny !Safe_ports
# Deny CONNECT to other than SSL ports
http_access deny CONNECT !SSL_ports
#
# We strongly recommend to uncomment the following to protect innocent
# web applications running on the proxy server who think that the only
# one who can access services on "localhost" is a local user
#http_access deny to_localhost
#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS

# Exampe rule allowing access from your local networks. Adapt
# to list your (internal) IP networks from where browsing should
# be allowed
#acl our_networks src 192.168.1.0/24 192.168.2.0/24
#http_access allow our_networks

# And finally deny all other access to this proxy
http_access allow all
http_access deny all

#  TAG: http_reply_access
#        Allow replies to client requests. This is complementary to http_access.
#
#        http_reply_access allow|deny [!] aclname ...
#
#        NOTE: if there are no access lines present, the default is to allow
#    all replies
#
#        If none of the access lines cause a match, then the opposite of
the
#        last line will apply. Thus it is good practice to end the rules
#        with an "allow all" or "deny all" entry.
#
#Default:
# http_reply_access allow all
#
#Recommended minimum configuration:
#
# Insert your own rules here.
#
#
# and finally allow by default
http_reply_access allow all

#  TAG: icp_access
#    Allowing or Denying access to the ICP port based on defined
#    access lists
#
#    icp_access  allow|deny [!]aclname ...
#
#    See http_access for details
#
#Default:
# icp_access deny all
#
#Allow ICP queries from everyone
icp_access allow all

#  TAG: miss_access
#    Use to force your neighbors to use you as a sibling instead of
#    a parent.  For example:
#
#        acl localclients src 172.16.0.0/16
#        miss_access allow localclients
#        miss_access deny  !localclients
#
#    This means that only your local clients are allowed to fetch
#    MISSES and all other clients can only fetch HITS.
#
#    By default, allow all clients who passed the http_access rules
#    to fetch MISSES from us.
#
#Default setting:
# miss_access allow all

#  TAG: cache_peer_access
#    Similar to 'cache_peer_domain' but provides more flexibility by
#    using ACL elements.
#
#    cache_peer_access cache-host allow|deny [!]aclname ...
#
#    The syntax is identical to 'http_access' and the other lists of
#    ACL elements.  See the comments for 'http_access' below, or
#    the Squid FAQ (http://www.squid-cache.org/FAQ/FAQ-10.html).
#
#Default:
# none

#  TAG: ident_lookup_access
#    A list of ACL elements which, if matched, cause an ident
#    (RFC 931) lookup to be performed for this request.  For
#    example, you might choose to always perform ident lookups
#    for your main multi-user Unix boxes, but not for your Macs
#    and PCs.  By default, ident lookups are not performed for
#    any requests.
#
#    To enable ident lookups for specific client addresses, you
#    can follow this example:
#
#    acl ident_aware_hosts src 198.168.1.0/255.255.255.0
#    ident_lookup_access allow ident_aware_hosts
#    ident_lookup_access deny all
#
#    Only src type ACL checks are fully supported.  A src_domain
#    ACL might work at times, but it will not always provide
#    the correct result.
#
#Default:
# ident_lookup_access deny all

#  TAG: tcp_outgoing_tos
#    Allows you to select a TOS/Diffserv value to mark outgoing
#    connections with, based on the username or source address
#    making the request.
#
#    tcp_outgoing_tos ds-field [!]aclname ...
#
#    Example where normal_service_net uses the TOS value 0x00
#    and normal_service_net uses 0x20
#
#    acl normal_service_net src 10.0.0.0/255.255.255.0
#    acl good_service_net src 10.0.1.0/255.255.255.0
#    tcp_outgoing_tos 0x00 normal_service_net 0x00
#    tcp_outgoing_tos 0x20 good_service_net
#
#    TOS/DSCP values really only have local significance - so you should
#    know what you're specifying. For more, see RFC 2474
#
#    The TOS/DSCP byte must be exactly that - a byte, value  0 - 255, or
#    "default" to use whatever default your host has.
#
#    Processing proceeds in the order specified, and stops at first fully
#    matching line.
#
#Default:
# none

#  TAG: tcp_outgoing_address
#    Allows you to map requests to different outgoing IP addresses
#    based on the username or sourceaddress of the user making
#    the request.
#   
#    tcp_outgoing_address ipaddr [[!]aclname] ...
#
#    Example where requests from 10.0.0.0/24 will be forwareded
#    with source address 10.1.0.1, 10.0.2.0/24 forwarded with
#    source address 10.1.0.2 and the rest will be forwarded with
#    source address 10.1.0.3.
#
#    acl normal_service_net src 10.0.0.0/255.255.255.0
#    acl good_service_net src 10.0.1.0/255.255.255.0
#    tcp_outgoing_address 10.0.0.1 normal_service_net
#    tcp_outgoing_address 10.0.0.2 good_service_net
#    tcp_outgoing_address 10.0.0.3
#
#    Processing proceeds in the order specified, and stops at first fully
#    matching line.
#
#Default:
# none

#  TAG: reply_body_max_size    bytes allow|deny acl acl...
#        This option specifies the maximum size of a reply body.  It
#    can be used to prevent users from downloading very large files,
#    such as MP3's and movies. When the reply headers are recieved,
#    the reply_body_max_size lines are processed, and the first line with
#    a result of "allow" is used as the maximum body size for this reply.
#    This size is then checked twice. First when we get the reply headers,
#    we check the content-length value.  If the content length value exists
#    and is larger than the allowed size, the request is denied and the
#    user receives an error message that says "the request or reply
#    is too large." If there is no content-length, and the reply
#    size exceeds this limit, the client's connection is just closed
#    and they will receive a partial reply.
#
#    WARNING: downstream caches probably can not detect a partial reply
#    if there is no content-length header, so they will cache
#    partial responses and give them out as hits.  You should NOT
#    use this option if you have downstream caches.
#
#    WARNING: A maximum size larger than the size of squid's error messages
#    will cause an infinite loop and crash squid. Ensure that the smallest
#    non-zero value you use is greater that the maximum header size plus
#    the size of your largest error page.
#
#    If you set this parameter to zero (the default), there will be
#    no limit imposed.
#
#Default:
# reply_body_max_size 0 allow all

# ADMINISTRATIVE PARAMETERS
# -----------------------------------------------------------------------------

#  TAG: cache_mgr
#    Email-address of local cache manager who will receive
#    mail if the cache dies.  The default is "webmaster."
#
#Default:
# cache_mgr webmaster

#  TAG: cache_effective_user
#  TAG: cache_effective_group
#
#    If the cache is run as root, it will change its effective/real
#    UID/GID to the UID/GID specified below.  The default is to
#    change to UID to nobody and GID to the default group of nobody.
#
#    If Squid is not started as root, the default is to keep the
#    current UID/GID, and only the GID can be changed to any of
#    the groups the user starting Squid is member of.  Note that if
#    Squid is not started as root then you cannot set http_port to
#    a value lower than 1024.
#
#Default:
# cache_effective_user nobody

#  TAG: visible_hostname
#    If you want to present a special hostname in error messages, etc,
#    then define this.  Otherwise, the return value of gethostname()
#    will be used. If you have multiple caches in a cluster and
#    get errors about IP-forwarding you must set them to have individual
#    names with this setting.
#
#Default:
# none

#  TAG: unique_hostname
#    If you want to have multiple machines with the same
#    'visible_hostname' then you must give each machine a different
#    'unique_hostname' so that forwarding loops can be detected.
#
#Default:
# none

#  TAG: hostname_aliases
#    A list of other DNS names that your cache has.
#
#Default:
# none


# OPTIONS FOR THE CACHE REGISTRATION SERVICE
# -----------------------------------------------------------------------------
#
#    This section contains parameters for the (optional) cache
#    announcement service.  This service is provided to help
#    cache administrators locate one another in order to join or
#    create cache hierarchies.
#
#    An 'announcement' message is sent (via UDP) to the registration
#    service by Squid.  By default, the announcement message is NOT
#    SENT unless you enable it with 'announce_period' below.
#
#    The announcement message includes your hostname, plus the
#    following information from this configuration file:
#
#        http_port
#        icp_port
#        cache_mgr
#
#    All current information is processed regularly and made
#    available on the Web at http://www.ircache.net/Cache/Tracker/.

#  TAG: announce_period
#    This is how frequently to send cache announcements.  The
#    default is `0' which disables sending the announcement
#    messages.
#
#    To enable announcing your cache, just uncomment the line
#    below.
#
#Default:
# announce_period 0
#
#To enable announcing your cache, just uncomment the line below.
#announce_period 1 day

#  TAG: announce_host
#  TAG: announce_file
#  TAG: announce_port
#    announce_host and announce_port set the hostname and port
#    number where the registration message will be sent.
#
#    Hostname will default to 'tracker.ircache.net' and port will
#    default default to 3131.  If the 'filename' argument is given,
#    the contents of that file will be included in the announce
#    message.
#
#Default:
# announce_host tracker.ircache.net
# announce_port 3131


# HTTPD-ACCELERATOR OPTIONS
# -----------------------------------------------------------------------------

#  TAG: httpd_accel_host
#  TAG: httpd_accel_port
#    If you want to run Squid as an httpd accelerator, define the
#    host name and port number where the real HTTP server is.
#
#    If you want IP based virtual host support then specify the
#    hostname as "virtual". This will make Squid use the IP address
#    where it accepted the request as hostname in the URL.
#
#    If you want virtual port support then specify the port as "0".
#
#    NOTE: enabling httpd_accel_host disables proxy-caching and
#    ICP.  If you want these features enabled also, then set
#    the 'httpd_accel_with_proxy' option.
#
#Default:
# httpd_accel_port 80

#  TAG: httpd_accel_single_host    on|off
#    If you are running Squid as an accelerator and have a single backend
#    server then set this to on. This causes Squid to forward the request
#    to this server irregardles of what any redirectors or Host headers
#    says.
#
#    Leave this at off if you have multiple backend servers, and use a
#    redirector (or host table or private DNS) to map the requests to the
#    appropriate backend servers. Note that the mapping needs to be a
#    1-1 mapping between requested and backend (from redirector) domain
#    names or caching will fail, as cacing is performed using the
#    URL returned from the redirector.
#
#    See also redirect_rewrites_host_header.
#
#Default:
# httpd_accel_single_host off

#  TAG: httpd_accel_with_proxy    on|off
#    If you want to use Squid as both a local httpd accelerator
#    and as a proxy, change this to 'on'. Note however that your
#    proxy users may have trouble to reach the accelerated domains
#    unless their browsers are configured not to use this proxy for
#    those domains (for example via the no_proxy browser configuration
#    setting)
#
#Default:
# httpd_accel_with_proxy off

#  TAG: httpd_accel_uses_host_header    on|off
#    HTTP/1.1 requests include a Host: header which is basically the
#    hostname from the URL.  The Host: header is used for domain based
#    virutal hosts. If your accelerator needs to provide domain based
#    virtual hosts on the same IP address then you will need to turn this
#    on.
#
#    Note that Squid does NOT check the value of the Host header matches
#    any of your accelerated server, so it may open a big security hole
#    unless you take care to set up access controls proper.  We recommend
#    that this option remain disabled unless you are sure of what you
#    are doing.
#
#    However, you will need to enable this option if you run Squid
#    as a transparent proxy.  Otherwise, virtual servers which
#    require the Host: header will not be properly cached.
#
#Default:
# httpd_accel_uses_host_header off


# MISCELLANEOUS
# -----------------------------------------------------------------------------

#  TAG: dns_testnames
#    The DNS tests exit as soon as the first site is successfully looked
up
#
#    This test can be disabled with the -D command line option.
#
#Default:
# dns_testnames netscape.com internic.net nlanr.net microsoft.com

#  TAG: logfile_rotate
#    Specifies the number of logfile rotations to make when you
#    type 'squid -k rotate'.  The default is 10, which will rotate
#    with extensions 0 through 9.  Setting logfile_rotate to 0 will
#    disable the rotation, but the logfiles are still closed and
#    re-opened.  This will enable you to rename the logfiles
#    yourself just before sending the rotate signal.
#
#    Note, the 'squid -k rotate' command normally sends a USR1
#    signal to the running squid process.  In certain situations
#    (e.g. on Linux with Async I/O), USR1 is used for other
#    purposes, so -k rotate uses another signal.  It is best to get
#    in the habit of using 'squid -k rotate' instead of 'kill -USR1
#    <pid>'.
#
#Default:
# logfile_rotate 10

#  TAG: append_domain
#    Appends local domain name to hostnames without any dots in
#    them.  append_domain must begin with a period.
#
#    Be warned that there today is Internet names with no dots in
#    them using only top-domain names, so setting this may
#    cause some Internet sites to become unavailable.
#
#Example:
# append_domain .yourdomain.com
#
#Default:
# none

#  TAG: tcp_recv_bufsize    (bytes)
#    Size of receive buffer to set for TCP sockets.  Probably just
#    as easy to change your kernel's default.  Set to zero to use
#    the default buffer size.
#
#Default:
# tcp_recv_bufsize 0 bytes

#  TAG: err_html_text
#    HTML text to include in error messages.  Make this a "mailto"
#    URL to your admin address, or maybe just a link to your
#    organizations Web page.
#
#    To include this in your error messages, you must rewrite
#    the error template files (found in the "errors" directory).
#    Wherever you want the 'err_html_text' line to appear,
#    insert a %L tag in the error template file.
#
#Default:
# none

#  TAG: deny_info
#    Usage:   deny_info err_page_name acl
#    Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
#
#    This can be used to return a ERR_ page for requests which
#    do not pass the 'http_access' rules.  A single ACL will cause
#    the http_access check to fail.  If a 'deny_info' line exists
#    for that ACL then Squid returns a corresponding error page.
#
#    You may use ERR_ pages that come with Squid or create your own pages
#    and put them into the configured errors/ directory.
#
#    Alternatively you can tell Squid to reset the TCP connection
#    by specifying TCP_RESET.
#
#Default:
# none

#  TAG: memory_pools    on|off
#    If set, Squid will keep pools of allocated (but unused) memory
#    available for future use.  If memory is a premium on your
#    system and you believe your malloc library outperforms Squid
#    routines, disable this.
#
#Default:
# memory_pools on

#  TAG: memory_pools_limit    (bytes)
#    Used only with memory_pools on:
#    memory_pools_limit 50 MB
#
#    If set to a non-zero value, Squid will keep at most the specified
#    limit of allocated (but unused) memory in memory pools. All free()
#    requests that exceed this limit will be handled by your malloc
#    library. Squid does not pre-allocate any memory, just safe-keeps
#    objects that otherwise would be free()d. Thus, it is safe to set
#    memory_pools_limit to a reasonably high value even if your
#    configuration will use less memory.
#
#    If not set (default) or set to zero, Squid will keep all memory it
#    can. That is, there will be no limit on the total amount of memory
#    used for safe-keeping.
#
#    To disable memory allocation optimization, do not set
#    memory_pools_limit to 0. Set memory_pools to "off" instead.
#
#    An overhead for maintaining memory pools is not taken into account
#    when the limit is checked. This overhead is close to four bytes per
#    object kept. However, pools may actually _save_ memory because of
#    reduced memory thrashing in your malloc library.
#
#Default:
# none

#  TAG: forwarded_for    on|off
#    If set, Squid will include your system's IP address or name
#    in the HTTP requests it forwards.  By default it looks like
#    this:
#
#        X-Forwarded-For: 192.1.2.3
#
#    If you disable this, it will appear as
#
#        X-Forwarded-For: unknown
#
#Default:
# forwarded_for on

#  TAG: log_icp_queries    on|off
#    If set, ICP queries are logged to access.log. You may wish
#    do disable this if your ICP load is VERY high to speed things
#    up or to simplify log analysis.
#
#Default:
# log_icp_queries on

#  TAG: icp_hit_stale    on|off
#    If you want to return ICP_HIT for stale cache objects, set this
#    option to 'on'.  If you have sibling relationships with caches
#    in other administrative domains, this should be 'off'.  If you only
#    have sibling relationships with caches under your control, then
#    it is probably okay to set this to 'on'.
#    If set to 'on', then your siblings should use the option "allow-miss"
#    on their cache_peer lines for connecting to you.
#
#Default:
# icp_hit_stale off

#  TAG: minimum_direct_hops
#    If using the ICMP pinging stuff, do direct fetches for sites
#    which are no more than this many hops away.
#
#Default:
# minimum_direct_hops 4

#  TAG: minimum_direct_rtt
#    If using the ICMP pinging stuff, do direct fetches for sites
#    which are no more than this many rtt milliseconds away.
#
#Default:
# minimum_direct_rtt 400

#  TAG: cachemgr_passwd
#    Specify passwords for cachemgr operations.
#
#    Usage: cachemgr_passwd password action action ...
#
#    Some valid actions are (see cache manager menu for a full list):
#        5min
#        60min
#        asndb
#        authenticator
#        cbdata
#        client_list
#        comm_incoming
#        config *
#        counters
#        delay
#        digest_stats
#        dns
#        events
#        filedescriptors
#        fqdncache
#        histograms
#        http_headers
#        info
#        io
#        ipcache
#        mem
#        menu
#        netdb
#        non_peers
#        objects
#        pconn
#        peer_select
#        redirector
#        refresh
#        server_list
#        shutdown *
#        store_digest
#        storedir
#        utilization
#        via_headers
#        vm_objects
#
#    * Indicates actions which will not be performed without a
#      valid password, others can be performed if not listed here.
#
#    To disable an action, set the password to "disable".
#    To allow performing an action without a password, set the
#    password to "none".
#
#    Use the keyword "all" to set the same password for all actions.
#
#Example:
# cachemgr_passwd secret shutdown
# cachemgr_passwd lesssssssecret info stats/objects
# cachemgr_passwd disable all
#
#Default:
# none

#  TAG: store_avg_object_size    (kbytes)
#    Average object size, used to estimate number of objects your
#    cache can hold.  See doc/Release-Notes-1.1.txt.  The default is
#    13 KB.
#
#Default:
# store_avg_object_size 13 KB

#  TAG: store_objects_per_bucket
#    Target number of objects per bucket in the store hash table.
#    Lowering this value increases the total number of buckets and
#    also the storage maintenance rate.  The default is 50.
#
#Default:
# store_objects_per_bucket 20

#  TAG: client_db    on|off
#    If you want to disable collecting per-client statistics, then
#    turn off client_db here.
#
#Default:
# client_db on

#  TAG: netdb_low
#  TAG: netdb_high
#    The low and high water marks for the ICMP measurement
#    database.  These are counts, not percents.  The defaults are
#    900 and 1000.  When the high water mark is reached, database
#    entries will be deleted until the low mark is reached.
#
#Default:
# netdb_low 900
# netdb_high 1000

#  TAG: netdb_ping_period
#    The minimum period for measuring a site.  There will be at
#    least this much delay between successive pings to the same
#    network.  The default is five minutes.
#
#Default:
# netdb_ping_period 5 minutes

#  TAG: query_icmp    on|off
#    If you want to ask your peers to include ICMP data in their ICP
#    replies, enable this option.
#
#    If your peer has configured Squid (during compilation) with
#    '--enable-icmp' then that peer will send ICMP pings to origin server
#    sites of the URLs it receives.  If you enable this option then the
#    ICP replies from that peer will include the ICMP data (if available).
#    Then, when choosing a parent cache, Squid will choose the parent with
#    the minimal RTT to the origin server.  When this happens, the
#    hierarchy field of the access.log will be
#    "CLOSEST_PARENT_MISS".  This option is off by default.
#
#Default:
# query_icmp off

#  TAG: test_reachability    on|off
#    When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
#    instead of ICP_MISS if the target host is NOT in the ICMP
#    database, or has a zero RTT.
#
#Default:
# test_reachability off

#  TAG: buffered_logs    on|off
#    cache.log log file is written with stdio functions, and as such
#    it can be buffered or unbuffered. By default it will be unbuffered.
#    Buffering it can speed up the writing slightly (though you are
#    unlikely to need to worry unless you run with tons of debugging
#    enabled in which case performance will suffer badly anyway..).
#
#Default:
# buffered_logs off

#  TAG: reload_into_ims    on|off
#    When you enable this option, client no-cache or ``reload''
#    requests will be changed to If-Modified-Since requests.
#    Doing this VIOLATES the HTTP standard.  Enabling this
#    feature could make you liable for problems which it
#    causes.
#   
#    see also refresh_pattern for a more selective approach.
#
#Default:
# reload_into_ims off

#  TAG: always_direct
#    Usage: always_direct allow|deny [!]aclname ...
#
#    Here you can use ACL elements to specify requests which should
#    ALWAYS be forwarded directly to origin servers.  For example,
#    to always directly forward requests for local servers use
#    something like:
#
#        acl local-servers dstdomain my.domain.net
#        always_direct allow local-servers
#
#    To always forward FTP requests directly, use
#
#        acl FTP proto FTP
#        always_direct allow FTP
#
#    NOTE: There is a similar, but opposite option named
#    'never_direct'.  You need to be aware that "always_direct deny
#    foo" is NOT the same thing as "never_direct allow foo".  You
#    may need to use a deny rule to exclude a more-specific case of
#    some other rule.  Example:
#
#        acl local-external dstdomain external.foo.net
#        acl local-servers dstdomain  .foo.net
#        always_direct deny local-external
#        always_direct allow local-servers
#
#    This option replaces some v1.1 options such as local_domain
#    and local_ip.
#
#Default:
# none

#  TAG: never_direct
#    Usage: never_direct allow|deny [!]aclname ...
#
#    never_direct is the opposite of always_direct.  Please read
#    the description for always_direct if you have not already.
#
#    With 'never_direct' you can use ACL elements to specify
#    requests which should NEVER be forwarded directly to origin
#    servers.  For example, to force the use of a proxy for all
#    requests, except those in your local domain use something like:
#
#        acl local-servers dstdomain .foo.net
#        acl all src 0.0.0.0/0.0.0.0
#        never_direct deny local-servers
#        never_direct allow all
#   
#    or if squid is inside a firewall and there is local intranet
#    servers inside the firewall then use something like:
#
#        acl local-intranet dstdomain .foo.net
#        acl local-external dstdomain external.foo.net
#        always_direct deny local-external
#        always_direct allow local-intranet
#        never_direct allow all
#   
#    This option replaces some v1.1 options such as inside_firewall
#    and firewall_ip.
#
#Default:
# none

#  TAG: header_access
#    Usage: header_access header_name allow|deny [!]aclname ...
#
#    WARNING: Doing this VIOLATES the HTTP standard.  Enabling
#    this feature could make you liable for problems which it
#    causes.
#
#    This option replaces the old 'anonymize_headers' and the
#    older 'http_anonymizer' option with something that is much
#    more configurable. This new method creates a list of ACLs
#    for each header, allowing you very fine-tuned header
#    mangling.
#
#    You can only specify known headers for the header name.
#    Other headers are reclassified as 'Other'. You can also
#    refer to all the headers with 'All'.
#
#    For example, to achieve the same behaviour as the old
#    'http_anonymizer standard' option, you should use:
#
#        header_access From deny all
#        header_access Referer deny all
#        header_access Server deny all
#        header_access User-Agent deny all
#        header_access WWW-Authenticate deny all
#        header_access Link deny all
#
#    Or, to reproduce the old 'http_anonymizer paranoid' feature
#    you should use:
#
#        header_access Allow allow all
#        header_access Authorization allow all
#        header_access Cache-Control allow all
#        header_access Content-Encoding allow all
#        header_access Content-Length allow all
#        header_access Content-Type allow all
#        header_access Date allow all
#        header_access Expires allow all
#        header_access Host allow all
#        header_access If-Modified-Since allow all
#        header_access Last-Modified allow all
#        header_access Location allow all
#        header_access Pragma allow all
#        header_access Accept allow all
#        header_access Accept-Charset allow all
#        header_access Accept-Encoding allow all
#        header_access Accept-Language allow all
#        header_access Content-Language allow all
#        header_access Mime-Version allow all
#        header_access Retry-After allow all
#        header_access Title allow all
#        header_access Connection allow all
#        header_access Proxy-Connection allow all
#        header_access All deny all
#
#    By default, all headers are allowed (no anonymizing is
#    performed).
#
#Default:
# none

#  TAG: header_replace
#    Usage:   header_replace header_name message
#    Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
#
#    This option allows you to change the contents of headers
#    denied with header_access above, by replacing them with
#    some fixed string. This replaces the old fake_user_agent
#    option.
#
#    By default, headers are removed if denied.
#
#Default:
# none

#  TAG: icon_directory
#    Where the icons are stored. These are normally kept in
#    /usr/local/squid/share/icons
#
#Default:
# icon_directory /usr/local/squid/share/icons
#  TAG: error_directory
#    If you wish to create your own versions of the default
#    (English) error files, either to customize them to suit your
#    language or company copy the template English files to another
#    directory and point this tag at them.
#
#Default:
# error_directory /usr/local/squid/share/errors/English

#  TAG: minimum_retry_timeout    (seconds)
#    This specifies the minimum connect timeout, for when the
#    connect timeout is reduced to compensate for the availability
#    of multiple IP addresses.
#
#    When a connection to a host is initiated, and that host has
#    several IP addresses, the default connection timeout is reduced
#    by dividing it by the number of addresses.  So, a site with 15
#    addresses would then have a timeout of 8 seconds for each
#    address attempted.  To avoid having the timeout reduced to the
#    point where even a working host would not have a chance to
#    respond, this setting is provided.  The default, and the
#    minimum value, is five seconds, and the maximum value is sixty
#    seconds, or half of connect_timeout, whichever is greater and
#    less than connect_timeout.
#
#Default:
# minimum_retry_timeout 5 seconds

#  TAG: maximum_single_addr_tries
#    This sets the maximum number of connection attempts for a
#    host that only has one address (for multiple-address hosts,
#    each address is tried once).
#
#    The default value is three tries, the (not recommended)
#    maximum is 255 tries.  A warning message will be generated
#    if it is set to a value greater than ten.
#
#Default:
# maximum_single_addr_tries 3

#  TAG: snmp_port
# Note: This option is only available if Squid is rebuilt with the
#       --enable-snmp option
#
#    Squid can now serve statistics and status information via SNMP.
#    By default it listens to port 3401 on the machine. If you don't
#    wish to use SNMP, set this to "0".
#
#Default:
# snmp_port 3401

#  TAG: snmp_access
# Note: This option is only available if Squid is rebuilt with the
#       --enable-snmp option
#
#    Allowing or denying access to the SNMP port.
#
#    All access to the agent is denied by default.
#    usage:
#
#    snmp_access allow|deny [!]aclname ...
#
#Example:
# snmp_access allow snmppublic localhost
# snmp_access deny all
#
#Default:
# snmp_access deny all

#  TAG: snmp_incoming_address
# Note: This option is only available if Squid is rebuilt with the
#       --enable-snmp option
#
#  TAG: snmp_outgoing_address
# Note: This option is only available if Squid is rebuilt with the
#       --enable-snmp option
#
#    Just like 'udp_incoming_address' above, but for the SNMP port.
#
#    snmp_incoming_address    is used for the SNMP socket receiving
#                messages from SNMP agents.
#    snmp_outgoing_address    is used for SNMP packets returned to SNMP
#                agents.
#
#    The default snmp_incoming_address (0.0.0.0) is to listen on all
#    available network interfaces.
#
#    If snmp_outgoing_address is set to 255.255.255.255 (the default)
#    then it will use the same socket as snmp_incoming_address. Only
#    change this if you want to have SNMP replies sent using another
#    address than where this Squid listens for SNMP queries.
#
#    NOTE, snmp_incoming_address and snmp_outgoing_address can not have
#    the same value since they both use port 3401.
#
#Default:
# snmp_incoming_address 0.0.0.0
# snmp_outgoing_address 255.255.255.255

#  TAG: as_whois_server
#    WHOIS server to query for AS numbers.  NOTE: AS numbers are
#    queried only when Squid starts up, not for every request.
#
#Default:
# as_whois_server whois.ra.net
# as_whois_server whois.ra.net

#  TAG: wccp_router
#    Use this option to define your WCCP ``home'' router for
#    Squid.   Setting the 'wccp_router' to 0.0.0.0 (the default)
#    disables WCCP.
#
#Default:
# wccp_router 0.0.0.0

#  TAG: wccp_version
#    According to some users, Cisco IOS 11.2 only supports WCCP
#    version 3.  If you're using that version of IOS, change
#    this value to 3.
#
#Default:
# wccp_version 4

#  TAG: wccp_incoming_address
#  TAG: wccp_outgoing_address
#        wccp_incoming_address   Use this option if you require WCCP
#                messages to be received on only one
#                interface.  Do NOT use this option if
#                you're unsure how many interfaces you
#                have, or if you know you have only one
#                interface.
#
#    wccp_outgoing_address    Use this option if you require WCCP
#                messages to be sent out on only one
#                interface.  Do NOT use this option if
#                you're unsure how many interfaces you
#                have, or if you know you have only one
#                interface.
#
#        The default behavior is to not bind to any specific address.
#
#        NOTE, wccp_incoming_address and wccp_outgoing_address can not have
#        the same value since they both use port 2048.
#
#Default:
# wccp_incoming_address 0.0.0.0
# wccp_outgoing_address 255.255.255.255


# DELAY POOL PARAMETERS (all require DELAY_POOLS compilation option)
# -----------------------------------------------------------------------------

#  TAG: delay_pools
# Note: This option is only available if Squid is rebuilt with the
#       --enable-delay-pools option
#
#    This represents the number of delay pools to be used.  For example,
#    if you have one class 2 delay pool and one class 3 delays pool, you
#    have a total of 2 delay pools.
#
#Default:
# delay_pools 0

#  TAG: delay_class
# Note: This option is only available if Squid is rebuilt with the
#       --enable-delay-pools option
#
#    This defines the class of each delay pool.  There must be exactly one
#    delay_class line for each delay pool.  For example, to define two
#    delay pools, one of class 2 and one of class 3, the settings above
#    and here would be:
#
#Example:
# delay_pools 2      # 2 delay pools
# delay_class 1 2    # pool 1 is a class 2 pool
# delay_class 2 3    # pool 2 is a class 3 pool
#
#    The delay pool classes are:
#
#        class 1        Everything is limited by a single aggregate
#                bucket.
#
#        class 2     Everything is limited by a single aggregate
#                bucket as well as an "individual" bucket chosen
#                from bits 25 through 32 of the IP address.
#
#        class 3        Everything is limited by a single aggregate
#                bucket as well as a "network" bucket chosen
#                from bits 17 through 24 of the IP address and a
#                "individual" bucket chosen from bits 17 through
#                32 of the IP address.
#
#    NOTE: If an IP address is a.b.c.d
#        -> bits 25 through 32 are "d"
#        -> bits 17 through 24 are "c"
#        -> bits 17 through 32 are "c * 256 + d"
#
#Default:
# none

#  TAG: delay_access
# Note: This option is only available if Squid is rebuilt with the
#       --enable-delay-pools option
#
#    This is used to determine which delay pool a request falls into.
#    The first matched delay pool is always used, i.e., if a request falls
#    into delay pool number one, no more delay are checked, otherwise the
#    rest are checked in order of their delay pool number until they have
#    all been checked.  For example, if you want some_big_clients in delay
#    pool 1 and lotsa_little_clients in delay pool 2:
#
#Example:
# delay_access 1 allow some_big_clients
# delay_access 1 deny all
# delay_access 2 allow lotsa_little_clients
# delay_access 2 deny all
#
#Default:
# none

#  TAG: delay_parameters
# Note: This option is only available if Squid is rebuilt with the
#       --enable-delay-pools option
#
#    This defines the parameters for a delay pool.  Each delay pool has
#    a number of "buckets" associated with it, as explained in the
#    description of delay_class.  For a class 1 delay pool, the syntax is:
#
#delay_parameters pool aggregate
#
#    For a class 2 delay pool:
#
#delay_parameters pool aggregate individual
#
#    For a class 3 delay pool:
#
#delay_parameters pool aggregate network individual
#
#    The variables here are:
#
#        pool        a pool number - ie, a number between 1 and the
#                number specified in delay_pools as used in
#                delay_class lines.
#
#        aggregate    the "delay parameters" for the aggregate bucket
#                (class 1, 2, 3).
#
#        individual    the "delay parameters" for the individual
#                buckets (class 2, 3).
#
#        network        the "delay parameters" for the network buckets
#                (class 3).
#
#    A pair of delay parameters is written restore/maximum, where restore
is
#    the number of bytes (not bits - modem and network speeds are usually
#    quoted in bits) per second placed into the bucket, and maximum is the
#    maximum number of bytes which can be in the bucket at any time.
#
#    For example, if delay pool number 1 is a class 2 delay pool as in the
#    above example, and is being used to strictly limit each host to 64kbps
#    (plus overheads), with no overall limit, the line is:
#
#delay_parameters 1 -1/-1 8000/8000
#
#    Note that the figure -1 is used to represent "unlimited".
#
#    And, if delay pool number 2 is a class 3 delay pool as in the above
#    example, and you want to limit it to a total of 256kbps (strict limit)
#    with each 8-bit network permitted 64kbps (strict limit) and each
#    individual host permitted 4800bps with a bucket maximum size of 64kb
#    to permit a decent web page to be downloaded at a decent speed
#    (if the network is not being limited due to overuse) but slow down
#    large downloads more significantly:
#
#delay_parameters 2 32000/32000 8000/8000 600/64000
#
#    There must be one delay_parameters line for each delay pool.
#
#Default:
# none

#  TAG: delay_initial_bucket_level    (percent, 0-100)
# Note: This option is only available if Squid is rebuilt with the
#       --enable-delay-pools option
#
#    The initial bucket percentage is used to determine how much is put
#    in each bucket when squid starts, is reconfigured, or first notices
#    a host accessing it (in class 2 and class 3, individual hosts and
#    networks only have buckets associated with them once they have been
#    "seen" by squid).
#
#Default:
# delay_initial_bucket_level 50

#  TAG: incoming_icp_average
#  TAG: incoming_http_average
#  TAG: incoming_dns_average
#  TAG: min_icp_poll_cnt
#  TAG: min_dns_poll_cnt
#  TAG: min_http_poll_cnt
#    Heavy voodoo here.  I can't even believe you are reading this.
#    Are you crazy?  Don't even think about adjusting these unless
#    you understand the algorithms in comm_select.c first!
#
#Default:
# incoming_icp_average 6
# incoming_http_average 4
# incoming_dns_average 4
# min_icp_poll_cnt 8
# min_dns_poll_cnt 8
# min_http_poll_cnt 8

#  TAG: max_open_disk_fds
#    To avoid having disk as the I/O bottleneck Squid can optionally
#    bypass the on-disk cache if more than this amount of disk file
#    descriptors are open.
#
#    A value of 0 indicates no limit.
#
#Default:
# max_open_disk_fds 0

#  TAG: offline_mode
#    Enable this option and Squid will never try to validate cached
#    objects.
#
#Default:
# offline_mode off

#  TAG: uri_whitespace
#    What to do with requests that have whitespace characters in the
#    URI.  Options:
#
#    strip:  The whitespace characters are stripped out of the URL.
#        This is the behavior recommended by RFC2616.
#    deny:   The request is denied.  The user receives an "Invalid
#        Request" message.
#    allow:  The request is allowed and the URI is not changed.  The
#        whitespace characters remain in the URI.  Note the
#        whitespace is passed to redirector processes if they
#        are in use.
#    encode:    The request is allowed and the whitespace characters are
#        encoded according to RFC1738.  This could be considered
#        a violation of the HTTP/1.1
#        RFC because proxies are not allowed to rewrite URI's.
#    chop:    The request is allowed and the URI is chopped at the
#        first whitespace.  This might also be considered a
#        violation.
#
#Default:
# uri_whitespace strip

#  TAG: broken_posts
#    A list of ACL elements which, if matched, causes Squid to send
#    an extra CRLF pair after the body of a PUT/POST request.
#
#    Some HTTP servers has broken implementations of PUT/POST,
#    and rely on an extra CRLF pair sent by some WWW clients.
#
#    Quote from RFC 2068 section 4.1 on this matter:
#
#      Note: certain buggy HTTP/1.0 client implementations generate an
#      extra CRLF's after a POST request. To restate what is explicitly
#      forbidden by the BNF, an HTTP/1.1 client must not preface or follow
#      a request with an extra CRLF.
#
#Example:
# acl buggy_server url_regex ^http://....
# broken_posts allow buggy_server
#
#Default:
# none

#  TAG: mcast_miss_addr
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM option
#
#    If you enable this option, every "cache miss" URL will
#    be sent out on the specified multicast address.
#
#    Do not enable this option unless you are are absolutely
#    certain you understand what you are doing.
#
#Default:
# mcast_miss_addr 255.255.255.255

#  TAG: mcast_miss_ttl
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_TTL option
#
#    This is the time-to-live value for packets multicasted
#    when multicasting off cache miss URLs is enabled.  By
#    default this is set to 'site scope', i.e. 16.
#
#Default:
# mcast_miss_ttl 16

#  TAG: mcast_miss_port
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM option
#
#    This is the port number to be used in conjunction with
#    'mcast_miss_addr'.
#
#Default:
# mcast_miss_port 3135

#  TAG: mcast_miss_encode_key
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM option
#
#    The URLs that are sent in the multicast miss stream are
#    encrypted.  This is the encryption key.
#
#Default:
# mcast_miss_encode_key XXXXXXXXXXXXXXXX

#  TAG: nonhierarchical_direct
#    By default, Squid will send any non-hierarchical requests
#    (matching hierarchy_stoplist or not cachable request type) direct
#    to origin servers.
#
#    If you set this to off, then Squid will prefer to send these
#    requests to parents.
#
#    Note that in most configurations, by turning this off you will only
#    add latency to these request without any improvement in global hit
#    ratio.
#
#    If you are inside an firewall then see never_direct instead of
#    this directive.
#
#Default:
# nonhierarchical_direct on

#  TAG: prefer_direct
#    Normally Squid tries to use parents for most requests. If you by some
#    reason like it to first try going direct and only use a parent if
#    going direct fails then set this to on.
#
#    By combining nonhierarchical_direct off and prefer_direct on you
#    can set up Squid to use a parent as a backup path if going direct
#    fails.
#
#Default:
# prefer_direct off

#  TAG: strip_query_terms
#    By default, Squid strips query terms from requested URLs before
#    logging.  This protects your user's privacy.
#
#Default:
# strip_query_terms on

#  TAG: coredump_dir
#    By default Squid leaves core files in the directory from where
#    it was started. If you set 'coredump_dir' to a directory
#    that exists, Squid will chdir() to that directory at startup
#    and coredump files will be left there.
#
#Default:
# coredump_dir none
#
# Leave coredumps in the first cache dir
coredump_dir /usr/local/squid/var/cache

#  TAG: redirector_bypass
#    When this is 'on', a request will not go through the
#    redirector if all redirectors are busy.  If this is 'off'
#    and the redirector queue grows too large, Squid will exit
#    with a FATAL error and ask you to increase the number of
#    redirectors.  You should only enable this if the redirectors
#    are not critical to your caching system.  If you use
#    redirectors for access control, and you enable this option,
#    then users may have access to pages that they should not
#    be allowed to request.
#
#Default:
# redirector_bypass off

#  TAG: ignore_unknown_nameservers
#    By default Squid checks that DNS responses are received
#    from the same IP addresses that they are sent to.  If they
#    don't match, Squid ignores the response and writes a warning
#    message to cache.log.  You can allow responses from unknown
#    nameservers by setting this option to 'off'.
#
#Default:
# ignore_unknown_nameservers on

#  TAG: digest_generation
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This controls whether the server will generate a Cache Digest
#    of its contents.  By default, Cache Digest generation is
#    enabled if Squid is compiled with USE_CACHE_DIGESTS defined.
#
#Default:
# digest_generation on

#  TAG: digest_bits_per_entry
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This is the number of bits of the server's Cache Digest which
#    will be associated with the Digest entry for a given HTTP
#    Method and URL (public key) combination.  The default is 5.
#
#Default:
# digest_bits_per_entry 5

#  TAG: digest_rebuild_period    (seconds)
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This is the number of seconds between Cache Digest rebuilds.
#
#Default:
# digest_rebuild_period 1 hour

#  TAG: digest_rewrite_period    (seconds)
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This is the number of seconds between Cache Digest writes to
#    disk.
#
#Default:
# digest_rewrite_period 1 hour

#  TAG: digest_swapout_chunk_size    (bytes)
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This is the number of bytes of the Cache Digest to write to
#    disk at a time.  It defaults to 4096 bytes (4KB), the Squid
#    default swap page.
#
#Default:
# digest_swapout_chunk_size 4096 bytes

#  TAG: digest_rebuild_chunk_percentage    (percent, 0-100)
# Note: This option is only available if Squid is rebuilt with the
#       --enable-cache-digests option
#
#    This is the percentage of the Cache Digest to be scanned at a
#    time.  By default it is set to 10% of the Cache Digest.
#
#Default:
# digest_rebuild_chunk_percentage 10

#  TAG: chroot
#    Use this to have Squid do a chroot() while initializing.  This
#    also causes Squid to fully drop root privileges after
#    initializing.  This means, for example, that if you use a HTTP
#    port less than 1024 and try to reconfigure, you will get an
#    error.
#
#Default:
# none

#  TAG: client_persistent_connections
#  TAG: server_persistent_connections
#    Persistent connection support for clients and servers.  By
#    default, Squid uses persistent connections (when allowed)
#    with its clients and servers.  You can use these options to
#    disable persistent connections with clients and/or servers.
#
#Default:
# client_persistent_connections on
# server_persistent_connections on

#  TAG: pipeline_prefetch
#    To boost the performance of pipelined requests to closer
#    match that of a non-proxied environment Squid can try to fetch
#    up to two requests in parallell from a pipeline.
#
#    Defaults to off for bandwidth management and access logging
#    reasons.
#
#Default:
# pipeline_prefetch off

#  TAG: extension_methods
#    Squid only knows about standardized HTTP request methods.
#    You can add up to 20 additional "extension" methods here.
#
#Default:
# none

#  TAG: high_response_time_warning    (msec)
#    If the one-minute median response time exceeds this value,
#    Squid prints a WARNING with debug level 0 to get the
#    administrators attention.  The value is in milliseconds.
#
#Default:
# high_response_time_warning 0

#  TAG: high_page_fault_warning
#    If the one-minute average page fault rate exceeds this
#    value, Squid prints a WARNING with debug level 0 to get
#    the administrators attention.  The value is in page faults
#    per second.
#
#Default:
# high_page_fault_warning 0

#  TAG: high_memory_warning
#    If the memory usage (as determined by mallinfo) exceeds
#    value, Squid prints a WARNING with debug level 0 to get
#    the administrators attention.
#
#Default:
# high_memory_warning 0

#  TAG: store_dir_select_algorithm
#    Set this to 'round-robin' as an alternative.
#
#Default:
# store_dir_select_algorithm least-load

#  TAG: forward_log
# Note: This option is only available if Squid is rebuilt with the
#       -DWIP_FWD_LOG option
#
#    Logs the server-side requests.
#
#    This is currently work in progress.
#
#Default:
# none

#  TAG: ie_refresh    on|off
#    Microsoft Internet Explorer up until version 5.5 Service
#    Pack 1 has an issue with transparent proxies, wherein it
#    is impossible to force a refresh.  Turning this on provides
#    a partial fix to the problem, by causing all IMS-REFRESH
#    requests from older IE versions to check the origin server
#    for fresh content.  This reduces hit ratio by some amount
#    (~10% in my experience), but allows users to actually get
#    fresh content when they want it.  Note that because Squid
#    cannot tell if the user is using 5.5 or 5.5SP1, the behavior
#    of 5.5 is unchanged from old versions of Squid (i.e. a
#    forced refresh is impossible).  Newer versions of IE will,
#    hopefully, continue to have the new behavior and will be
#    handled based on that assumption.  This option defaults to
#    the old Squid behavior, which is better for hit ratios but
#    worse for clients using IE, if they need to be able to
#    force fresh content.
#
#Default:
# ie_refresh off

#  TAG: vary_ignore_expire    on|off
#    Many HTTP servers supporting Vary gives such objects
#    immediate expiry time with no cache-control header
#    when requested by a HTTP/1.0 client. This option
#    enables Squid to ignore such expiry times until
#    HTTP/1.1 is fully implemented.
#    WARNING: This may eventually cause some varying
#    objects not intended for caching to get cached.
#
#Default:
# vary_ignore_expire off

#  TAG: sleep_after_fork    (microseconds)
#    When this is set to a non-zero value, the main Squid process
#    sleeps the specified number of microseconds after a fork()
#    system call. This sleep may help the situation where your
#    system reports fork() failures due to lack of (virtual)
#    memory. Note, however, that if you have a lot of child
#    processes, then these sleep delays will add up and your
#    Squid will not service requests for some amount of time
#    until all the child processes have been started.
#
#Default:
# sleep_after_fork 0

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