SquidによるProxyサーバの構築

　Proxyサーバに多くの種類があるが，本研修では，UNIXで動作し，キャッシュサーバに機能に特化した「Squid」を使用する。UNIXで動作する他のProxyサーバとしてはApacheのProxyやCERN HTTPDやDelegateなどある。

　エディタで，/etc/squid/squid.confを開き，次に示す　　　個所を変更する。

＜省略＞約19行目

# NETWORK OPTIONS
# -----------------------------------------------------------------------------
# TAG: http_port
# The port number where Squid will listen for HTTP client
# requests. Default is 3128, for httpd-accel mode use port 80.
# May be overridden with -a on the command line.
#
# You may specify multiple ports here, but they MUST all be on
# a single line.
#
#http_port 3128
プロキシーのポート番号を指定，デフォルトでは３１２８
http_port 8080

# TAG: icp_port
# The port number where Squid sends and receives ICP requests to
# and from neighbor caches. Default is 3130. To disable use
# "0". May be overridden with -u on the command line.
#
#icp_port 3130
# TAG: htcp_port
# The port number where Squid sends and receives ICP requests to
# and from neighbor caches. Default is 4827. To disable use
# "0".
#
# To enable this option, you must use --enable-htcp with the
# configure script.
#htcp_port 4827

＜省略＞約190行目

#
# NOTE: non-ICP neighbors must be specified as 'parent'.
#
#cache_peer hostname type 3128 3130

＜省略＞約３４５行目

# The default is 8 Megabytes.
#

キャッシュに使うメモリ量，搭載メモリが豊富ならば増やせばよいが，デフォルトでかまわない

cache_mem 8 MB

# TAG: cache_swap_low (percent, 0-100)
# TAG: cache_swap_high (percent, 0-100)
# The low- and high-water marks for cache LRU replacement. LRU
# replacement begins when the high-water mark is reached and ends
# when enough objects have been removed and the low-water mark is
# reached. 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.
#
#cache_swap_low 90
#cache_swap_high 95
# 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.
#

どれくらいのサイズのファイルまでキャッシュするの指定。デフォルトは４MBである。

特に変更は不要

maximum_object_size 4096 KB

＜省略＞約７３０行目

# TAG: reference_age
# As a part of normal operation, Squid performs Least Recently
# Used removal of cached objects. The LRU age for removal is
# computed dynamically, based on the amount of disk space in
# use. The dynamic value can be seen in the Cache Manager 'info'
# output.
#
# The 'reference_age' parameter defines the maximum LRU age. For
# example, setting reference_age to '1 week' will cause objects
# to be removed if they have not been accessed for a week or
# more. The default value is one month.
#
# Specify a number here, followed by units of time. For example:
# 1 week
# 3.5 days
# 4 months
# 2.2 hours
#

どれくらいの期間キャッシュを持ち続けるかの設定。デフォルトは１ヶ月，3　daysとかでよいかも

reference_age 1 month

＜省略＞約９９０行目

#Examples:
#acl myexample dst_as 1241
#acl password proxy_auth REQUIRED
#
#Defaults:
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 SSL_ports port 443 563
acl Safe_ports port 80 21 443 563 70 210 1025-65535
acl CONNECT method CONNECT

proxyサーバを利用できるホストを定義，

192.168.1.xのIPアドレスのクライアントをlocalnetとして定義している

acl localnet src 192.168.1.0/255.255.255.0

# TAG: http_access
# Allowing or Denying access based on defined access lists
#
# Access to the HTTP port:
# http_access allow|deny [!]aclname ...
#
# Access to the ICP port:
# icp_access allow|deny [!]aclname ...
#
# NOTE on default values:
#
# If there are no "access" lines present, the default is to allow
# 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 configuration:
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
#
http_access allow localhost
Proxyを利用できるものとして，前述のacl名であるlocalnetを許可する

http_access allow localnet

http_access deny all

squid.confの設定で，以下のようにキャッシュサイズ500MBに増や設定をしたところ，Restartがひたすら時間がかかり，うまくいかなかった。

最近の，squid.confを見たところ，以下のように「ufs」がついているではないか！