DHCP配置手册

snow chuai汇总、整理、撰写---2020/1/20

1. 基本拓扑

DHCP SRV:192.168.188.10/24

|------------|        |------------|
 |  DHCP Srv  | -eth0- |    Router  | 
|------------|        |------------|

2. DHCP安装

[root@node1 ~]# yum install dhcp -y

3. DHCP配置模板所在位置

[root@node1 ~]# ls -l /usr/share/doc/dhcp-$version/dhcpd.conf.example

4. 配置DHCP服务器单一作用域

[root@node1 ~]# vim /etc/dhcp/dhcpd.conf
# 配置DNS域名
option domain-name “1000cc.net”;

# 配置DNS服务器IP地址
option domain-name-servers 192.168.188.3, 114.114.114.114;

# 设定default及max租约
default-lease-time 600;
max-lease-time 7200;

# 设定日志记录
log-facility local7;

# 设定单区域DHCP分配网络段为192.168.188.0/24
# 分配地址为120-220,路由为.192.168.188.1
subnet 192.168.188.0 netmask 255.255.255.0 {
range 192.168.188.100 192.168.188.199;
option routers 192.168.188.1;
}
#设定指定客户端获取自定IP地址
host snow {
option host-name "snow.1000cc.net";
hardware ethernet 00:01:02:03:04:05;
fixed-address 192.168.188.250;
}

# 启动dhcpd服务
[root@node1 ~]# systemctl enable --now dhcpd
[root@node1 ~]# systemctl status dhcpd

# 设定防火墙
[root@node1 ~]# firewall-cmd --add-service=dhcp --permanent
[root@node1 ~]# firewall-cmd --reload

5.客户端配置

1) 安装DHC客户端工具  
[root@node2 ~]# yum install dhclient -y

2) 手动获取IP地址
[root@node2 ~]# dhclient  eth0

3) 显示租约过程
[root@node2 ~]# dhclient -v eth0

4) 指定DHCP[服务器](#dhcpsrv)
[root@node2 ~]# dhclient -s 192.168.188.10 -v eth0

5) 停止DHCP客户端并释放租约
[root@node2 ~]# dhclient  eth0 -r

6. 租约文件位置

1) 服务器端租约文件位置
[root@node1 ~]# ls /var/lib/dhcpd/dhcpd.leases

2) 客户端租约文件位置
[root@node2 ~]# ls /var/lib/dhclient/dhclient.leases

7. DHCP中继代理

7.1 拓扑

DHCP SRV:192.168.188.10/24 
Router-eth0192.168.188.1/24		Router-eth0:192.168.166.1/24
|------------|        |------------|	    |------------|
|  DHCP Srv  | -eth0- |    Router  | -eth1- | DHCP Client|
|------------|        |------------|        |------------|

7.2 实现DHCP中继代理(多作用域)

1) 在服务器端再添加一个对DHCP Client所分配的网络
[root@node1 ~]# vim /etc/dhcp/dhcpd.conf
option domain-name “1000cc.net”;
option domain-name-servers 192.168.188.3, 114.114.114.114;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;

subnet 192.168.188.0 netmask 255.255.255.0 {
  range 192.168.188.100 192.168.188.199;
  option routers 192.168.188.1;
}

# 增加DHCP Client的网络地址，并设定分配的IP
subnet 192.168.166.0 netmask 255.255.255.0 {
  range 192.168.166.100 192.168.166.199;
  option routers 192.168.166.1;
}

2) 于Router处安装DHCP Relay
[root@node1 ~]# yum install dhcp -y

3) 配置dhcp relay
[root@node1 ~]# vim /usr/lib/systemd/system/dhcrelay.service
# 找到以下字段 
ExecStart=/usr/sbin/dhcrelay -d --no-pid  

# 改为以下内容，并指定好DHCP SRV
ExecStart=/usr/sbin/dhcrelay -d --no-pid -i eth1 -i eth0 192.168.188.10

4) 启动dhcp relay服务
[root@node1 ~]# systemctl daemon-reload
[root@node1 ~]# systemctl enable --now dhcrelay

5) [客户端](#dhcpclient)测试

8. 共享作用域

[root@node1 ~]# vim /etc/dhcp/dhcpd.conf
option domain-name “1000cc.net”;

option domain-name-servers 192.168.188.3, 114.114.114.114;

default-lease-time 600;

max-lease-time 7200;

log-facility local7;

# 添加共享作用域niliu
shared-network niliu {
subnet 192.168.188.0 netmask 255.255.255.0 {
  range 192.168.188.100 192.168.188.199;
  option routers 192.168.188.1;
}

subnet 192.168.166.0 netmask 255.255.255.0 {
  range 192.168.166.100 192.168.166.199;
  option routers 192.168.166.1;
}
}

[root@node1 ~]# systemctl restart dhcpd

9. 分配客户端指定IP地址

[root@node1 ~]# vim /etc/dhcp/dhcpd.conf
option domain-name “1000cc.net”;
option domain-name-servers 192.168.188.3, 114.114.114.114;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;

subnet 192.168.188.0 netmask 255.255.255.0 {
  range 192.168.188.100 192.168.188.199;
  option routers 192.168.188.1;
}

# 设定指定客户端获取自定IP地址
host snow {
  option host-name "snow.1000cc.net";
  hardware ethernet 00:01:02:03:04:05;
  fixed-address 192.168.188.250;
}

[root@node1 ~]# systemctl restart dhcpd

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