Linux系统中配置DHCP服务器中继代理

假设一台计算机做软路由，有三个网卡，连接3个不同的网段，192.168.1.1/24, 192.168.2.1/24,192.168.3.1/24;其中192.168.1.1/24这个网段有一个DHCP服务器，那怎么样设置可以使192.168.2.1/24和192.168.3.1/24这两个网段分配IP呢？

首先得在dhcp.conf文件中添加超级作用域：

ddns-update-style interim; ;指定DHCP支持的DNS动态更新为interim
ignore client-updates; ;指定不允许客户机更新DNS记录。
shared-network xxxdhcp { ；超级作用域名为xxxdhcp
option subnet-mask 255.255.255.0;
option domain-name-servers 192.168.1.2,192.168.1.10,192.168.4.1;
option broadcast-address 192.168.1.255;
default-lease-time 86400;
max-lease-time 172800;
}

subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.21 192.168.1.49;
option routers 192.168.1.1;
host pc1 {
hardware ethernet MAC;
fixed-address 192.168.1.20;
}
}

subnet 192.168.2.0 netmask 255.255.255.0 {
range 192.168.2.21 192.168.2.49;
option routers 192.168.2.1;
host pc1 {
hardware ethernet MAC;
fixed-address 192.168.2.20;
}
}

subnet 192.168.3.0 netmask 255.255.255.0 {
range 192.168.3.21 192.168.3.49;
option routers 192.168.3.1;
host pc1 {
hardware ethernet MAC;
fixed-address 192.168.3.20;
}
}

linux下的DHCP客户端：/etc/sysconfig/network-scripts/ifcfg-eth0把BOOTPROTO="none"修改为BOOTPROTO="dhcp"

如果需要在系统启动时自动引导启动联网，/etc/sysconfig/networking下的networking=yes。