同事们总是抱怨上国外网站速度很慢，半天网页都打不开，于是使用squid和ipfilter实现透明代理，为他们提供缓存功能。
@ 安装squid
为了偷懒就直接使用ports安装，因为我将所有的服务器系统都安装在/s分区中，所以设置了PREFIX为/s/squid
# cd /usr/ports/www/squid
# setenv PREFIX /s/squid
# make install clean
安装完成后编辑/s/squid/etc/squid/squid.conf，我的配置内容如下：
########## Base control ##########
cache_mgr webmaster
cache_effective_user squid
cache_effective_group squid
visible_hostname sleepcat.3322.org
http_port 127.0.0.1:3128
icp_port 0
cache_dir ufs /usr/cache 300 16 256
cache_access_log /dev/null
cache_log /dev/null
cache_store_log /dev/null
error_directory /s/squid/etc/squid/errors/Simplify_Chinese
icon_directory /s/squid/etc/squid/icons
mime_table /s/squid/etc/squid/mime.conf
coredump_dir /s/squid/squid/cache
pid_filename /s/squid/squid/logs/squid.pid
hosts_file /etc/hosts
unlinkd_program /s/squid/libexec/squid/unlinkd########## Performance control ##########
cache_mem 8 MB
cache_swap_low 90
cache_swap_high 95
maximum_object_size 4096 KB
minimum_object_size 0 KB
maximum_object_size_in_memory 8 KB
ipcache_size 1024
ipcache_low 90
ipcache_high 95
fqdncache_size 1024
cache_replacement_policy lru
memory_replacement_policy lru
emulate_httpd_log off
log_ip_on_direct on
log_mime_hdrs off
dns_timeout 2 minutes
request_header_max_size 10 KB
request_body_max_size 0 KB
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern . 0 20% 4320
negative_ttl 5 minutes
positive_dns_ttl 6 hours
negative_dns_ttl 1 minute
connect_timeout 1 minute
read_timeout 15 minutes
request_timeout 5 minutes
client_lifetime 1 day
half_closed_clients on
maximum_single_addr_tries 1
uri_whitespace strip
ie_refresh off
########## Access control ############
acl all src 0.0.0.0/0.0.0.0
http_access allow all
http_reply_access allow all
hierarchy_stoplist cgi-bin ?
########## Accelator control ############
httpd_accel_host virtual
httpd_accel_port 80
httpd_accel_with_proxy on
httpd_accel_uses_host_header on
########## Misc control ###########
ftp_user Squid@
ftp_list_width 32
ftp_passive on
ftp_sanitycheck on
初始化cache
# /s/squid/sbin/squid -z启动squid
# /s/squid/etc/rc.d/squid.sh start@ 设置ipfilter
为了实现透明的功能，需要将所有对80端口的请求转到squid的3128端口上，以实现对客户端透明的功能。在/etc/ipnat.rules中加入:
rdr fxp1 0.0.0.0/0 port 80 -> 127.0.0.1 3128
刷新ipnat配置：
# ipnat -Cf /etc/ipnat.rules
一切完成，客户端无需任何设置，根本感觉不到代理的存在，而且访问速度明显变快。