5.1)DHCP服务配置

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

option domain-name-servers 4.2.2.2, 4.2.2.1;

default-lease-time 28800;

max-lease-time 43200;

authoritative;

log-facility local7;

subnet 192.168.11.0 netmask 255.255.255.0 {

range 192.168.11.153 192.168.11.252;

option domain-name-servers 202.106.0.20, 114.114.114.114;

option routers 192.168.11.254;

option broadcast-address 192.168.11.255;

default-lease-time 7200;

max-lease-time 10800;

}

请根据4.2中的讲解理解配置文件内容。

5.2）重启DHCP服务，生效配置

#重启dhcpd服务

[root@baism dhcp]# systemctl restart dhcpd

#查看启动情况，同时也验证了客户端使用的是68端口，服务端使用的是67端口

[root@baism dhcp]# lsof -i :68

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

dhclient 55234 root 6u IPv4 110700 0t0 UDP *:bootpc

[root@baism dhcp]# lsof -i :67

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

dnsmasq 1507 nobody 3u IPv4 27149 0t0 UDP *:bootps

dhcpd 56570 dhcpd 7u IPv4 129157 0t0 UDP *:bootps

5.3）测试IP分发

打开一个客户端机器，IP获得方式为自动获取，测试是否获得到了自己这个DHCP服务器发放的IP地址。本例子中测试机使用了centos 6.5系统。来看下测试结果吧！

1) 查看一下当前eth0的IP地址、MAC地址，并保证其IP获得方式为:DHCP

[root@bogon 桌面]# ifconfig eth0

eth0 Link encap:Ethernet HWaddr 00:0C:29:1A:F8:BD

inet addr:172.16.44.132 Bcast:172.16.44.255 Mask:255.255.255.0

inet6 addr: fe80::20c:29ff:fe1a:f8bd/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:86 errors:0 dropped:0 overruns:0 frame:0

TX packets:63 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:15294 (14.9 KiB) TX bytes:6769 (6.6 KiB)

2）使用dhclient命令来获得IP，看一下重要输出

[root@bogon 桌面]# dhclient -d eth0

Internet Systems Consortium DHCP Client 4.1.1-P1

Copyright 2004-2010 Internet Systems Consortium.

All rights reserved.

For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/00:0c:29:1a:f8:bd

Sending on LPF/eth0/00:0c:29:1a:f8:bd

Sending on Socket/fallback

DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6 (xid=0x316768c3) 发广播寻找DHCP服务器

DHCPOFFER from 192.168.11.16 192.168.11.16DHCP服务器应答

DHCPREQUEST on eth0 to 255.255.255.255 port 67 (xid=0x316768c3) client向服务器请求IP地址

DHCPACK from 192.168.11.16 (xid=0x316768c3) 确认租赁关系

bound to 192.168.11.156 -- renewal in 2983 seconds. client分得IP:192.168.11.156

^C

注意：看到这些信息后，按CTRL+C退出。

dhclient是一个DHCP协议客户端，它使用DHCP协议或者BOOTP协议或在这两个协议都不可用时使用静态地址来配置一个或多个网络接口

dhclient -r 释放IP地址

dhclient -d 强制dhclient作为前台进程运行。 通常情况下，DHCP客户端将在前台运行,直到配置了一个接口,此时它将恢复为在后

台运行。

3) 服务器日志查看验证获取信息

[root@baism ~]# tailf /var/log/messages

Feb 21 13:40:44 baism dhcpd: DHCPDISCOVER from 00:0c:29:1a:f8:bd via ens33

Feb 21 13:40:45 baism dhcpd: DHCPOFFER on 192.168.11.156 to 00:0c:29:1a:f8:bd via ens33

Feb 21 13:40:45 baism dhcpd: DHCPREQUEST for 192.168.11.156 (192.168.11.16) from 00:0c:29:1a:f8:bd via ens33

Feb 21 13:40:45 baism dhcpd: DHCPACK on 192.168.11.156 to 00:0c:29:1a:f8:bd via ens33

4) 在client上通过ifconfig命令再次查看eth0 IP地址，验证是否为192.168.11.156

[root@bogon 桌面]# ifconfig eth0

eth0 Link encap:Ethernet HWaddr 00:0C:29:1A:F8:BD

inet addr:192.168.11.156 Bcast:192.168.11.255 Mask:255.255.255.0

inet6 addr: fe80::20c:29ff:fe1a:f8bd/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:97 errors:0 dropped:0 overruns:0 frame:0

TX packets:67 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:17364 (16.9 KiB) TX bytes:7537 (7.3 KiB)

5）查看网关，确定网关为192.168.11.254

[root@bogon 桌面]# route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

192.168.11.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1

192.168.11.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

169.254.0.0 0.0.0.0 255.255.0.0 U 1003 0 0 eth1

0.0.0.0 192.168.11.254 0.0.0.0 UG 0 0 0 eth0

6）查看DNS配置文件，看DNS是否为DHCP服务器发放的DNS服务器IP

[root@bogon 桌面]# cat /etc/resolv.conf

; generated by /sbin/dhclient-script

nameserver 202.106.0.20

nameserver 114.114.114.114