观天Linux7建立DHCP服务器，为网络主机分配IP地址。以下是组网网络拓扑图：
建立顺序：
一、Linux安装 DHCP服务 命令：yum install -y dhcp
二、复制Linux系统自带的DHCP配置模板。 命令：cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example ./dhcpd.conf
三、配置DHCP服务的配置文件vi /etc/dhcp/dhcp.conf，添加了三个网段的配置。
命令：vi /etc/dhcp/dhcp.conf
添加：
subnet 10.10.10.0 netmask 255.255.255.0 { /DHCP地址池
range 10.10.10.11 10.10.10.252;
option domain-name-servers 114.114.114.114; /DNS地址
option domain-name "xiaolan";
option routers 10.10.10.254; /本网段网关地址
option broadcast-address 10.10.10.255; /本网段广播地址
default-lease-time 600;
max-lease-time 7200;
}
subnet 10.2.20.0 netmask 255.255.255.0 {
range 10.2.20.11 10.2.20.252;
option domain-name-servers 114.114.114.114;
option domain-name "xiaolan20";
option routers 10.2.20.254;
option broadcast-address 10.2.20.255;
default-lease-time 600;
max-lease-time 7200;
}
subnet 10.2.30.0 netmask 255.255.255.0 {
range 10.2.30.11 10.2.30.252;
option domain-name-servers 114.114.114.114;
option domain-name "xiaolan30";
option routers 10.2.30.254;
option broadcast-address 10.2.30.255;
default-lease-time 600;
max-lease-time 7200;
}
四、重启：systemctl restart dhcpd ，DHCP服务器状态查看 systemctl status dhcpd
五、配置交换机开启DHCP服务，开启DHCP中继，即可分发多网段IP。
交换机配置参考：
sys # sysname SW1 # vlan batch 10 20 30 # dhcp enable # vlan 10 description DHCP # interface Vlanif10 ip address 10.10.10.254 255.255.255.0 dhcp select relay dhcp relay server-ip 10.10.10.10 # interface Vlanif20 ip address 10.2.20.254 255.255.255.0 dhcp select relay dhcp relay server-ip 10.10.10.10 # interface Vlanif30 ip address 10.2.30.254 255.255.255.0 dhcp select relay dhcp relay server-ip 10.10.10.10 # interface GigabitEthernet0/0/1 port link-type access port default vlan 10 # interface GigabitEthernet0/0/2 port link-type access port default vlan 20 # interface GigabitEthernet0/0/3 port link-type access port default vlan 30
