CentOS做路由器

系统版本:centos6.9

硬件:eth0和eth1口的x86服务器

需求:eth0作为外网接口.eth1桥接br0接口通过nat后上网

1.配置eth0

[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

HWADDR=00:30:18:0B:AF:80

TYPE=Ethernet

UUID=5ad1f1fa-18e8-495d-9938-b8f1c9343aa3

ONBOOT=yes

NM_CONTROLLED=yes

BOOTPROTO=static

IPADDR=192.168.14.200

NETMASK=255.255.255.0

GATEWAY=192.168.14.1

DNS1=192.168.14.1

DNS2=114.114.114.114

2.配置br桥接口

[root@localhost ~]# brctl addbr br0

[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-br0

DEVICE="br0"

ONBOOT=yes

NETBOOT=yes

IPV6INIT=yes

BOOTPROTO=none

TYPE=Bridge

NM_CONTROLLED=no

NAME="br0"

IPADDR=192.168.188.22

NETMASK=255.255.255.0

[root@localhost ~]# brctl addif br0 eth1      #将eth1加入br0

[root@localhost ~]# brctl show                     #查看已有网桥检查是否加入成功

bridge name bridge id STP enabled interfaces

br0 8000.0030180baf81 no eth1

3.开启系统的ip转发功能

[root@localhost ~]#  echo "1">/proc/sys/net/ipv4/ip_forward

或者

[root@localhost ~]# vi /etc/sysctl.conf

设置：

net.ipv4.ip_forward = 1

[root@localhost ~]#  sysctl -p            #检查是否修改成功

4.修改防火墙,添加NAT规则 (删除其他无用规则,有需要再添加)

[root@localhost ~]# vi /etc/sysconfig/iptables

# Generated by iptables-save v1.4.7 on Wed Mar 28 00:00:11 2018

*nat

:PREROUTING ACCEPT [0:0]

:POSTROUTING ACCEPT [1:108]

:OUTPUT ACCEPT [1:108]

-A POSTROUTING -s 192.168.1.0/24 -j SNAT --to-source 192.168.14.200    #添加NAT规则

-A POSTROUTING -s 192.168.1.0/24 -o eth0 -j MASQUERADE         #添加NAT规则

COMMIT

# Completed on Wed Mar 28 00:00:11 2018

# Generated by iptables-save v1.4.7 on Wed Mar 28 00:00:11 2018

*filter

:INPUT ACCEPT [38:4567]

:FORWARD ACCEPT [4968:5721817]

:OUTPUT ACCEPT [31:3336]

COMMIT

# Completed on Wed Mar 28 00:00:11 2018