1.安装dhcp软件

注意：安装时需要有配置好的yum仓库，关于yum仓库的配置，祥见Linux下系统的软件安装以及yum源配置(yum仓库搭建、yum命令、rpm命令)

[root@servser ~]# yum install dhcp -y

Loaded plugins: langpacks

Resolving Dependencies

--> Running transaction check

---> Package dhcp.x86_64 12:4.2.5-27.el7 will be installed

--> Finished Dependency Resolution

Dependencies Resolved

================================================================================

Package       Arch            Version                   Repository        Size

================================================================================

Installing:

dhcp          x86_64          12:4.2.5-27.el7           rhel7.0          506 k

Transaction Summary

================================================================================

Install  1 Package

Total download size: 506 k

Installed size: 1.4 M

Downloading packages:

dhcp-4.2.5-27.el7.x86_64.rpm                               | 506 kB   00:00

Running transaction check

Running transaction test

Transaction test succeeded

Running transaction

Installing : 12:dhcp-4.2.5-27.el7.x86_64                                  1/1

Verifying  : 12:dhcp-4.2.5-27.el7.x86_64                                  1/1

Installed:

dhcp.x86_64 12:4.2.5-27.el7

Complete!

2.配置动态网络

注意：配置防火墙关闭或者将dhcp服务加入防火墙白名单，详见LInux下防火墙的基本管理(查看、火墙伪装、添加防火墙白名单)

[root@servser ~]# systemctl start dhcpd                                          ##安装完成后打开dhcpd服务

[root@servser ~]# systemctl status dhcpd.service                           ##可以看到，服务打不开

dhcpd.service - DHCPv4 Server Daemon

Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled)

Active: failed (Result: exit-code) since Mon 2019-02-18 11:52:33 EST; 13s ago

Docs: man:dhcpd(8)

man:dhcpd.conf(5)

Process: 31524 ExecStart=/usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid (code=exited, status=1/FAILURE)

Main PID: 31524 (code=exited, status=1/FAILURE)

Feb 18 11:52:33 servser.westos.com dhcpd[31524]: you want, please write a su...n

Feb 18 11:52:33 servser.westos.com dhcpd[31524]: in your dhcpd.conf file for...t

Feb 18 11:52:33 servser.westos.com dhcpd[31524]: to which interface eth0 is ...*

Feb 18 11:52:33 servser.westos.com dhcpd[31524]: Feb 18 11:52:33 servser.westos.com dhcpd[31524]: Feb 18 11:52:33 servser.westos.com dhcpd[31524]: Not configured to listen on...!

Feb 18 11:52:33 servser.westos.com dhcpd[31524]: Feb 18 11:52:33 servser.westos.com dhcpd[31524]: This version of ISC DHCP is...e

Feb 18 11:52:33 servser.westos.com systemd[1]: dhcpd.service: main process e...E

Feb 18 11:52:33 servser.westos.com systemd[1]: Unit dhcpd.service entered fa....

Hint: Some lines were ellipsized, use -l to show in full.

[root@servser ~]# vim /etc/dhcp/dhcpd.conf              ##打开配置文件，发现配置文件为空，需要查看模板

[root@servser ~]# cat /etc/dhcp/dhcpd.conf

#

# DHCP Server Configuration file.

#   see /usr/share/doc/dhcp*/dhcpd.conf.example

#   see dhcpd.conf(5) man page

#

[root@servser ~]# cp /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcpd.conf                 ##复制模板过来

cp: overwrite ‘/etc/dhcp/dhcpd.conf’? y

[root@servser ~]# vim /etc/dhcp/dhcpd.conf                                         ##编辑动态网络配置文件

##写入：

# dhcpd.conf

#

# Sample configuration file for ISC dhcpd

#

# option definitions common to all supported networks...

option domain-name "westos.com";

option domain-name-servers 172.25.68.100;

default-lease-time 600;

max-lease-time 7200;

# Use this to enble / disable dynamic dns updates globally.

#ddns-update-style none;

# If this DHCP server is the official DHCP server for the local

# network, the authoritative directive should be uncommented.

#authoritative;

# Use this to send dhcp log messages to a different log file (you also

# have to hack syslog.conf to complete the redirection).

log-facility local7;

# No service will be given on this subnet, but declaring it helps the

# DHCP server to understand the network topology.

# This is a very basic subnet declaration.

subnet 172.25.68.0 netmask 255.255.255.0 {

range 172.25.68.101 172.25.68.200;

option routers 172.25.68.100;

}

##其中：

option domain-name "westos.com";

option domain-name-servers 172.25.68.100;

DNS，配置获取到网络的DNS服务域名和域名服务器的IP

default-lease-time 600;

默认租约时间

max-lease-time 7200;

最大租约时间

subnet 172.25.68.0

netmask 255.255.255.0

子网掩码

range 172.25.68.101 172.25.68.200;

可获取的动态IP范围

option routers 172.25.68.100;

获取到网络的网关

3.测试动态网络源：

[root@dhcp_test ~]# ifconfig                                                                                            ##查看当前已有的IP

eth0: flags=4163mtu 1500

inet 172.25.68.101  netmask 255.255.255.0  broadcast 172.25.68.255

inet6 fe80::5054:ff:fe00:440b  prefixlen 64  scopeid 0x20

ether 52:54:00:00:44:0b  txqueuelen 1000  (Ethernet)

RX packets 370  bytes 35553 (34.7 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 338  bytes 36819 (35.9 KiB)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163mtu 1500

ether 52:54:00:24:53:64  txqueuelen 1000  (Ethernet)

RX packets 156  bytes 10332 (10.0 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 0  bytes 0 (0.0 B)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73mtu 65536

inet 127.0.0.1  netmask 255.0.0.0

inet6 ::1  prefixlen 128  scopeid 0x10loop  txqueuelen 0  (Local Loopback)

RX packets 275  bytes 22000 (21.4 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 275  bytes 22000 (21.4 KiB)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@dhcp_test ~]# cd /etc/sysconfig/network-scripts/                   ##切换目录

[root@dhcp_test network-scripts]# ls

ifcfg-eth0-1  ifdown-ppp       ifup-eth     ifup-sit

ifcfg-lo      ifdown-routes    ifup-ippp    ifup-Team

ifdown        ifdown-sit       ifup-ipv6    ifup-TeamPort

ifdown-bnep   ifdown-Team      ifup-isdn    ifup-tunnel

ifdown-eth    ifdown-TeamPort  ifup-plip    ifup-wireless

ifdown-ippp   ifdown-tunnel    ifup-plusb   init.ipv6-global

ifdown-ipv6   ifup             ifup-post    network-functions

ifdown-isdn   ifup-aliases     ifup-ppp     network-functions-ipv6

ifdown-post   ifup-bnep        ifup-routes

[root@dhcp_test network-scripts]# cp ifcfg-eth0-1 ifcfg-eth1                       ##复制配置文件

[root@dhcp_test network-scripts]# vim ifcfg-eth1                                         ##编辑配置文件

##写入

TYPE=Ethernet

BOOTPROTO=dhcp

NAME=eth1

ONBOOT=yes

DEVICE=eth1

[root@dhcp_test network-scripts]# systemctl restart network重启网络服务

[root@dhcp_test network-scripts]# ifconfig

eth0: flags=4163mtu 1500

inet 172.25.68.101  netmask 255.255.255.0  broadcast 172.25.68.255

inet6 fe80::5054:ff:fe00:440b  prefixlen 64  scopeid 0x20

ether 52:54:00:00:44:0b  txqueuelen 1000  (Ethernet)

RX packets 1469  bytes 130431 (127.3 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 1048  bytes 121340 (118.4 KiB)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163mtu 1500

inet 172.25.68.108  netmask 255.255.255.0  broadcast 172.25.68.255       ##可以看到eth1成功获得到了动态IP

inet6 fe80::5054:ff:fe24:5364  prefixlen 64  scopeid 0x20

ether 52:54:00:24:53:64  txqueuelen 1000  (Ethernet)

RX packets 360  bytes 20100 (19.6 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 22  bytes 3891 (3.7 KiB)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73mtu 65536

inet 127.0.0.1  netmask 255.0.0.0

inet6 ::1  prefixlen 128  scopeid 0x10loop  txqueuelen 0  (Local Loopback)

RX packets 275  bytes 22000 (21.4 KiB)

RX errors 0  dropped 0  overruns 0  frame 0

TX packets 275  bytes 22000 (21.4 KiB)

TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

##查看日志也可以看到动态IP获取的来源

Feb 18 12:50:43 localhost NetworkManager: DHCPREQUEST on eth1 to 255.255.255.255 port 67 (xid=0x410b580d)

Feb 18 12:50:43 localhost dhclient[4482]: DHCPACK from 172.25.68.100 (xid=0x410b580d)

Feb 18 12:50:43 localhost NetworkManager: DHCPACK from 172.25.68.100 (xid=0x410b580d)

Feb 18 12:50:43 localhost dhclient[4482]: bound to 172.25.68.108 -- renewal in 234 seconds.

Feb 18 12:50:43 localhost NetworkManager: bound to 172.25.68.108 -- renewal in 234 seconds.

Feb 18 12:50:43 localhost NetworkManager[664]: (eth1): DHCPv4 state changed preinit -> reboot

Feb 18 12:50:43 localhost NetworkManager[664]: address 172.25.68.108

Feb 18 12:50:43 localhost NetworkManager[664]: plen 24 (255.255.255.0)

Feb 18 12:50:43 localhost NetworkManager[664]: gateway 172.25.68.100

Feb 18 12:50:43 localhost NetworkManager[664]: server identifier 172.25.68.100

Feb 18 12:50:43 localhost NetworkManager[664]: lease time 600

Feb 18 12:50:43 localhost NetworkManager[664]: nameserver '172.25.68.100'

Feb 18 12:50:43 localhost NetworkManager[664]: domain name 'westos.com'