DHCP 服务器

文章目录

• DHCP 服务器
• • DHCP 服务介绍
  • DHCP 通信过程
  • 多 DHCP 服务器场景
  • DHCP 服务器部署
  • • 安装 DHCP 软件包
    • 文件配置
    • 启用并启动服务
    • 客户端配置
  • 基于 MAC 地址的 IP 预留
  • • 配置步骤

DHCP 服务器

DHCP 服务介绍

DHCP（Dynamic Host Configuration Protocol）即动态主机配置协议，是一种应用于局域网的网络协议，采用 UDP 协议和 C/S 模式，用于集中管理和分配 IP 地址等网络参数。

DHCP 通信过程

租约续约流程

多 DHCP 服务器场景

冲突处理机制

DHCP 服务器部署

安装 DHCP 软件包

[root@server ~ 10:11:58]# yum install -y dhcp

文件配置

配置参数说明

[root@server ~ 10:11:58]# cat /etc/dhcp/dhcpd.conf
#
# DHCP Server Configuration file.
# see /usr/share/doc/dhcp*/dhcpd.conf.example
# see dhcpd.conf(5) man page
#
[root@server ~ 10:13:02]# cp /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcpd.conf
cp：是否覆盖"/etc/dhcp/dhcpd.conf"？ y
[root@server ~ 10:13:52]# vim /etc/dhcp/dhcpd.conf
[root@server ~ 16:51:37]# cat /etc/dhcp/dhcpd.conf
# option definitions common to all supported networks…
# 设置域名
option domain-name "yang.cloud";
#设置DNS
option domain-name-servers 223.5.5.5, 223.6.6.6;

#默认租约时间
default-lease-time 600;
#最大租约时间
max-lease-time 7200;

#日志级别
log-facility local7;

#配置DHCP池
subnet 10.1.8.0 netmask 255.255.255.0 {
range 10.1.8.101 10.1.8.130;
#option domain-name-servers ns1.internal.example.org;
#option domain-name "internal.example.org";
option routers 10.1.8.2;
option broadcast-address 10.1.8.255;
#default-lease-time 600;
#max-lease-time 7200;
}
# Fixed IP addresses can also be specified for hosts. These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP. Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.
#根据Mac地址配置固定IP
host fantasia {
hardware ethernet 08:00:07:26:c0:a5;
fixed-address fantasia.fugue.com;
}

启用并启动服务

[root@server ~ 10:39:41]# systemctl enable dhcpd –now
Created symlink from /etc/systemd/system/multi-user.target.wants/dhcpd.service to /usr/lib/systemd/system/dhcpd.service.
[root@server ~ 10:39:55]# systemctl status dhcpd
● dhcpd.service – DHCPv4 Server Daemon
Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; enabled; vendor preset: disabled)
Active: active (running) since 四 2025-09-25 10:39:55 CST; 12s ago
...
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)

客户端配置

在客户端添加一张NAT网卡

[root@client ~ 10:41:26]# ip -br a
lo UNKNOWN 127.0.0.1/8 ::1/128
ens33 UP 10.1.8.11/24 fe80::20c:29ff:fef5:b10b/64
ens37 UP 10.1.8.101/24 fe80::fef1:2cec:159a:4343/64

基于 MAC 地址的 IP 预留

应用场景

为 Web 服务器、数据库服务器等需要固定 IP 的设备，绑定 MAC 地址与 IP，确保每次分配相同 IP。

配置步骤

查看客户端 MAC 地址

[root@client ~ 11:08:28]# ip -br link
lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
ens33 UP 00:0c:29:f5:b1:0b <BROADCAST,MULTICAST,UP,LOWER_UP>
ens37 UP 00:0c:29:f5:b1:15 <BROADCAST,MULTICAST,UP,LOWER_UP>

修改 DHCP 服务器配置

在/etc/dhcp/dhcpd.conf末尾添加

# Fixed IP addresses can also be specified for hosts. These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP. Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.
#根据Mac地址配置固定IP
host client.cloud {
hardware ethernet 00:0c:29:f5:b1:15;
# 预留的固定IP为10.1.8.100
fixed-address 10.1.8.100;
}

重启 DHCP 服务

[root@server ~ 11:08:51]# systemctl restart dhcpd

客户端验证

[root@client ~ 11:09:33]# ip -br a
lo UNKNOWN 127.0.0.1/8 ::1/128
ens33 UP 10.1.8.11/24 fe80::20c:29ff:fef5:b10b/64
ens37 UP 10.1.8.100/24 fe80::fef1:2cec:159a:4343/64