Linux DHCP 下自定义路由和网关

主机IP必须通过DHCP获得,但是因故需要重新指定网关并做策略路由。例如主机DHCP获取IP段192.168.1.0/24,DHCP获取网关192.168.1.1,拟将默认路由改为192.168.1.2,本地IP仍然走网关192.168.1.1

RHEL(CentOS) 6/7

/etc/sysconfig/network-scripts/ifcfg-eth0
BOOTPROTO=dhcp
NM_CONTROLLED="no"
ONBOOT=yes
GATEWAY=192.168.1.2
……

/etc/sysconfig/network-scripts/route-eth0
192.168.0.0/16 via 192.168.1.1

/etc/sysconfig/network
NETWORKING=yes
……

Debian 7

/etc/network/interfaces
……
up route del default dev eth0
up route add -net 192.168.1.0 netmask 255.255.255.0 gw 192.168.1.1 dev eth0
up route add default gw 192.168.1.2 dev eth0
……

Suse 11

/etc/sysconfig/network/routes
……
192.168.0.0 192.168.1.1 255.255.0.0 eth0
default 192.168.1.2 - -

 

使用PF实现基于来源的策略路由

  FreeBSD做服务器,要实现从哪个网卡进来的连接请求,返回时还从哪个网卡出去。这样可以让客户端自己选择线路,无需收集路由表。

ee /etc/rc.conf
pf_enable="YES"
pf_rules="/etc/pf.conf"

//启用PF
defaultrouter="192.168.1.1"
//这个是本机自己发起连接的默认路由

ee /etc/pf.conf

if_cernet="em0"
if_ct="em1"
gw_cernet="192.168.1.1"
gw_ct="192.168.0.1"
block all
pass quick on lo0 all
pass in quick on $if_cernet reply-to ( $if_cernet $gw_cernet ) proto {tcp,udp,icmp} to any keep state
pass in quick on $if_ct reply-to ( $if_ct $gw_ct ) proto {tcp,udp,icmp} to any keep state
pass out keep state