换来换去感觉太凌乱所以可以分为三个步骤：

第一部分：服务器设置

DHCP服务器器调整： [root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens32 TYPE=Ethernet PROXY_METHOD=none
BROWSER_ONLY=no BOOTPROTO=static DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=no IPV6_DEFROUTE=no IPV6_FAILURE_FATAL=no IPV6_ADDR_GEN_MODE=stable-privacy NAME=ens32 UUID=b194e583-21c3-4109-a160-3d2a9876a30b DEVICE=ens32 ONBOOT=yes IPADDR=192.168.200.111 PREFIX=24 GATEWAY=192.168.200.112 //⽹网关需要指向DHCP中继服务器器同⽹网络的IP地址 DNS1=202.106.0.20 IPV6_PRIVACY=no
 
[root@localhost ~]# ifconfig ens32 //VMnet8模式 ens32: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        inet 192.168.200.111  netmask 255.255.255.0  broadcast 192.168.200.255        inet6 fe80::20c:29ff:feb6f933c  prefixlen 64  scopeid 0x20<link>        ether 00f0c:29:b6f93f3c  txqueuelen 1000  (Ethernet)        RX packets 12335  bytes 5849822 (5.5 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 9984  bytes 1934256 (1.8 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
 
[root@localhost ~]# vim /etc/dhcp/dhcpd.conf option domain-name "crushlinux.com"; option domain-name-servers 202.106.0.20, 8.8.8.8; default-lease-time 21600;
max-lease-time 43200;
 
subnet 192.168.200.0 netmask 255.255.255.0 {  range 192.168.200.150 192.168.200.200;  option routers 192.168.200.1; }
 
subnet 192.168.100.0 netmask 255.255.255.0 {  range 192.168.100.150 192.168.100.200;  option routers 192.168.100.1; } [root@localhost ~]# systemctl restart dhcpd

第二部分：中继服务器设置

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens32 TYPE=Ethernet PROXY_METHOD=none BROWSER_ONLY=no BOOTPROTO=static DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=no IPV6_DEFROUTE=no IPV6_FAILURE_FATAL=no IPV6_ADDR_GEN_MODE=stable-privacy NAME=ens32 UUID=b194e583-21c3-4109-a160-3d2a9876a30b IPV6_PRIVACY=no DEVICE=ens32 ONBOOT=yes IPADDR=192.168.200.112 //需作为DHCP服务器器的⽹网关地址 NETMASK=255.255.255.0 [root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens34
TYPE=Ethernet PROXY_METHOD=none BROWSER_ONLY=no BOOTPROTO=static DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=no IPV6_DEFROUTE=no IPV6_FAILURE_FATAL=no IPV6_ADDR_GEN_MODE=stable-privacy NAME=ens34 IPV6_PRIVACY=no DEVICE=ens34 ONBOOT=yes IPADDR=192.168.100.112 NETMASK=255.255.255.0
 
[root@localhost ~]# ip a | grep ens 2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    inet 192.168.200.112/24 brd 192.168.200.255 scope global ens32 3: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    inet 192.168.100.112/24 brd 192.168.100.255 scope global ens34
 
[root@localhost ~]# rpm -ivh /media/cdrom/Packages/dhcp-4.2.568.el7.centos.x86_64.rpm [root@localhost ~]# rpm -ql dhcp |grep dhcrelay /usr/lib/systemd/system/dhcrelay.service /usr/sbin/dhcrelay /usr/share/man/man8/dhcrelay.8.gz
 
打开DHCP中继服务器器路路由转发功能
[root@localhost ~]# vim /etc/sysctl.conf net.ipv4.ip_forward = 1 [root@localhost ~]# sysctl -p
 
开启DHCP中继服务 [root@localhost ~]# dhcrelay 192.168.200.111 Dropped all unnecessary capabilities. Internet Systems Consortium DHCP Relay Agent 4.2.5 Copyright 2004-2013 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/virbr0/52f54f00:b3:df:0e Sending on   LPF/virbr0/52f54f00:b3:df:0e Listening on LPF/ens34/00f0c:29f8c:f2:e3 Sending on   LPF/ens34/00f0c:29f8c:f2:e3 Listening on LPF/ens32/00f0c:29f8c:f2:d9 Sending on   LPF/ens32/00f0c:29f8c:f2:d9 Sending on   Socket/fallback
 
[root@localhost ~]# netstat -anpu | grep dhcrelay udp        0      0 0.0.0.0f67              0.0.0.0:*                           2893/dhcrelay

第三部分：测试

当客户机在VMnet2⽹网络时：    当客户机在VMnet8⽹网络时：