图示说明：
1.IP规划设置
| 主机名 | ip地址 | ip地址(第二个网卡配置的地址) | 地址类别 |
| oldboy01 | 192.168.10.20 | 空 | 仅可访问内网主机 |
| oldboy02 | 192.168.10.10 | 10.0.0.10 | 可访问内外网主机 |
2.修改网卡配置及iptables配置
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开始修改oldboy01（LAN）主机配置
[[email protected] ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
IPADDR=192.168.10.20 #设置网卡ip
NETMASK=255.255.255.0 # 设置掩码
GATEWAY=192.168.10.10 #修改网关配置为oldboy2局域网IP地址
DNS1=223.5.5.5 #设置DNS,如果不设置DNS，则无法ping通域名
USERCTL=no
PEERDNS=yes
IPV6INIT=no
显示oldboy01的路由：
完成oldboy01的修改
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2.开始oldboy02（WLAN）的设置
1 [[email protected] ~]# echo "1"> /proc/sys/net/ipv4/ip_forward #修改当前系统内存中ip_forward的值，这是开启ip转发 2 [[email protected] ~]# cat /proc/sys/net/ipv4/ip_forward 3 14 [[email protected] ~]# sysctl -p
1 [[email protected] ~]# echo -e "# Controls IP packet forwarding\nnet.ipv4.ip_forward = 1 " >>/etc/sysctl.conf #将ip转发参数，写入内容到配置文件，每次启动机器时都会开启ip转发功能 2 [[email protected] ~]# tail -3 /etc/sysctl.conf 3 # Controls IP packet forwarding 4 net.ipv4.ip_forward = 1
- [[email protected] /]# iptables -t nat -A POSTROUTING -o eth0 -s 192.168.10.0/24 -j SNAT --to 10.0.0.10 #将内网出口规则写入到iptables内存中
- [[email protected] /]# service iptables save #保存设置
- #将上面写入的内容保存到文件中
- iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ] #上面规则写入的配置文件/etc/sysconfig/iptables
- [[email protected] /]# /etc/init.d/iptables restart #重启iptables
- iptables: Setting chains to policy ACCEPT: nat filter [ OK ]
- iptables: Flushing firewall rules: [ OK ]
- iptables: Unloading modules: [ OK ]
- iptables: Applying firewall rules: [ OK ]
- [[email protected] /]# iptables-save #显示iptables规则（iptables-save可以显示iptables配置文件及内存中新添加的规则）
- # Generated by iptables-save v1.4.7 on Thu Nov 2 14:24:33 2017
- *filter
- :INPUT ACCEPT [10:720]
- :FORWARD ACCEPT [0:0]
- :OUTPUT ACCEPT [7:1032]
- -A OUTPUT -p tcp -m tcp --dport 80 -j ACCEPT
- COMMIT
- # Completed on Thu Nov 2 14:24:33 2017
- # Generated by iptables-save v1.4.7 on Thu Nov 2 14:24:33 2017
- *nat
- :PREROUTING ACCEPT [0:0]
- :POSTROUTING ACCEPT [1:120]
- :OUTPUT ACCEPT [1:120]
- -A POSTROUTING -s 192.168.10.0/24 -o eth0 -j SNAT --to-source 10.0.0.10 #之前追加的iptables规则
- COMMIT
- # Completed on Thu Nov 2 14:24:33 2017
完成修改oldboy02主机配置 3.测试是否可以访问外网oldboy01
原文地址：https://www.cnblogs.com/Mercury-linux/p/11617262.html