Linux系统之DHCP网络协议

一、DHCP概述

二、DHCP部署实操

2.1、安装DHCP软件

2.2、拷贝配置文件

2.3、配置文件详解

2.4、重启软件服务

2.5、新开一台服务器，查看dhcp地址获取

一、DHCP概述

DHCP（Dynamic Host Configuration Protocol）是一种应用层网络协议，用于动态分配IP地址和其他网络配置信息给网络中的设备（如计算机、路由器、打印机等）。DHCP是一个客户端-服务器协议，其中DHCP 服务器会为连接到网络中的DHCP 客户端分配 IP 地址、子网掩码、默认网关、DNS 服务器等信息，从而简化了设备配置。

DHCP工作原理

客户端发送DHCPDISCOVER广播消息。
DHCP 服务器收到消息后，发送DHCPOFFER响应，提供一个可用的 IP 地址。
客户端选择其中一个DHCPOFFER，并发送DHCPQUEST请求使用该 IP 地址。
服务器确认请求，发送DHCPACK，正式分配IP地址。
客户端配置网络并开始使用分配的IP地址。

二、DHCP部署实操

2.1、安装DHCP软件

[root@localhost ~]# systemctl stop firewalld.service     //关闭防火墙
[root@localhost ~]# setenforce 0                         //关闭selinux
[root@localhost ~]# yum install dhcp -y            //安装软件
[root@localhost ~]# rpm -qc dhcp                   //查看配置文件
/etc/dhcp/dhcpd.conf
/etc/dhcp/dhcpd6.conf
/etc/openldap/schema/dhcp.schema
/etc/sysconfig/dhcpd
/var/lib/dhcpd/dhcpd.leases
/var/lib/dhcpd/dhcpd6.leases

2.2、拷贝配置文件

[root@localhost dhcp]# ls /etc/dhcp/
dhclient.d  dhclient-exit-hooks.d  dhcpd6.conf  dhcpd.conf  scripts
[root@localhost dhcp]# cat dhcpd.conf 
#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.example    //dhcp配置文件范本，直接拷贝并修改
#   see dhcpd.conf(5) man page
#
[root@localhost dhcp]# cp /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcp.conf
[root@localhost dhcp]# vim /etc/dhcp/dhcp.conf

2.3、配置文件详解

  6 # option definitions common to all supported networks...
  7 option domain-name "example.org";                               //dns服务器域名
  8 option domain-name-servers ns1.example.org, ns2.example.org;    //dns服务器地址
  9 
 10 default-lease-time 600;
 11 max-lease-time 7200;
 12 

 20 # Use this to send dhcp log messages to a different log file (you also
 21 # have to hack syslog.conf to complete the redirection).
 22 log-facility local7;        //日志设施类型
 23 

 46 # A slightly different configuration for an internal subnet.
 47 subnet 10.5.5.0 netmask 255.255.255.224 {               //分配的网段，拷贝整段进行重新配置
 48   range 10.5.5.26 10.5.5.30;                            //分配的地址范围
 49   option domain-name-servers ns1.internal.example.org;  
 50   option domain-name "internal.example.org";
 51   option routers 10.5.5.1;                              //指定网关地址
 52   option broadcast-address 10.5.5.31;
 53   default-lease-time 600;
 54   max-lease-time 7200;
 55 }
 75 host fantasia {                                         //主机分配固定IP地址
 76   hardware ethernet 08:00:07:26:c0:a5;                  //绑定MAC地址
 77   fixed-address fantasia.fugue.com;                     //保留的IP地址
 78 }

 //在空行处粘贴范文
 27 subnet 192.168.153.0 netmask 255.255.255.0 {       //DHCP服务器网段与子网掩码
 28   range 192.168.153.20 192.168.153.100;            //分配的地址范围
 30   option routers 192.168.153.2;                    //网关地址
 31   default-lease-time 600;                          //租约时间
 32 }

2.4、重启软件服务

[root@localhost dhcp]# systemctl restart dhcpd
● dhcpd.service - DHCPv4 Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled; vendor preset: disabled)
   Active: active (running) since 三 2025-02-26 22:28:19 CST; 4min 13s ago
     Docs: man:dhcpd(8)
           man:dhcpd.conf(5)
 Main PID: 2671 (dhcpd)
   Status: "Dispatching packets..."
    Tasks: 1