环境如下：
操作系统：CentOS 6.4
eth0:192.168.100.1 （LAN口）
eth1:200.168.10.1 (WAN口)
一.iptables的配置
1.啟動ip_forward(IP轉發)
修改/etc/sysctl.conf
將net.ipv4.ip_forward = 1
并運行sysctl -p，使之生效
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[root@nagios~]
# vim /etc/sysctl.conf
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[root@nagios ~]
# sysctl -p
net.ipv4.ip_forward = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
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2.清空iptables所有表的規則并查看nat表
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[root@nagios ~]
# iptables -F
[root@nagios ~]
# iptables -t nat -F
[root@nagios ~]
# iptables -t mangle -F
[root@nagios ~]
# iptables -t nat -L
Chain PREROUTING (policy ACCEPT)
target prot opt
source
destination
Chain POSTROUTING (policy ACCEPT)
target prot opt
source
destination
Chain OUTPUT (policy ACCEPT)
target prot opt
source
destination
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3.设置端口重定向
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[root@nagios ~]
# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3128
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#在NAT表的PREROUTING鏈加目標動作REDIRECT，將入站的數據包進行重定向，將80端口重定向到3128端口
4.设置iptables路由DNS数据
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[root@nagios~]
#iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -p udp --dport 53 -d 202.96.128.86 -j SNAT --to-source 200.168.10.1
[root@nagios~]
#iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -p tcp --dport 53 -d 202.96.128.86 -j SNAT --to-source 200.168.10.1
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說明：可以看出上面DNS是通過服務器的NAT功能來實現，202.96.128.86是外部DNS服務器地址，而200.168.10.1是我們WAN口的IP。如果外部DNS服務器經常變更的話，可以直接將DNS忽略掉:
iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -p tcp --dport 53 -j SNAT --to-source 200.168.10.1
iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -p udp --dport 53 -j SNAT --to-source 200.168.10.1
5.保存iptables设置及重启iptables服务
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[root@Nagios ~]
# service iptables save
[root@Nagios ~]
# service iptables restart
iptables: Saving firewall rules to
/etc/sysconfig/iptables
:[ OK ]
[root@Nagios ~]
# iptables -t nat -L
Chain PREROUTING (policy ACCEPT)
target prot opt
source
destination
REDIRECT tcp -- 192.168.10.0
/24
anywhere tcp dpt:http redir ports 3128
Chain POSTROUTING (policy ACCEPT)
target prot opt
source
destination
SNAT udp -- 192.168.10.0
/24
202.96.128.86 udp dpt:domain to:200.168.10.1
SNAT tcp -- 192.168.10.0
/24
202.96.128.86 tcp dpt:domain to:200.168.10.1
Chain OUTPUT (policy ACCEPT)
target prot opt
source
destination
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二.Squid的安装与配置
我們使用yum來安裝Squid:
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[root@nagios ~]
# yum -y install squid
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備份squid的配置文件，防止因為配置錯誤
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[root@nagios ~]
# cp /etc/squid/squid.conf /etc/squid/squid.conf_bak
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配置squid.conf
找到
http_port 3128修改成http_port 192.168.100.10:3128 transparent
并添加
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visible_hostname squid
acl innet src 192.168.10.0
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http_access allow innet
http_access deny all
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下面就運行squid -z進行初始化
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[root@nagios ~]
# squid -z
2013
/05/29
13:41:43| Creating Swap Directories
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啟動squid代理服務器
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[root@nagios ~]
# service squid start
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重新啟動iptables服務
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[root@nagios ~]
# service iptables restart
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并將squid及iptables設置成開機啟動
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[root@nagios ~]
# chkconfig --level 35 squid on
[root@nagios ~]
# chkconfig --level 35 iptables on
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客户端网络设置： DNS设置为转发的DNS IP
其他设置：
隐藏错误页面Squid版本
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httpd_suppress_version_string on
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不记录访问日志
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cache_store_log none
cache_access_log
/dev/null
cache_log
/dev/null
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隐藏Header头部信息(3.0以后版本)
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request_header_access Via deny all
request_header_access Server deny all
request_header_access X-Cache deny all
request_header_access X-Cache-Lookup deny all
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如果是2.8之前的版本
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header_access Via deny all
header_access Server deny all
header_access X-Cache deny all
header_access X-Cache-Lookup deny all
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