linux系統中部署DHCP服務并驗證

DHCP（Dynamic Host Configuration Protocal）工作模式為伺服器/用戶端；

DHCP主要用于自動為用戶端配置設定網卡資訊，比如自動配置設定IP、網關等。

準備三台虛拟機，主機名分别為PC1、PC2和PC3，均為RHEL7，PC1作為伺服器，PC2和PC3作為用戶端。

1、檢視伺服器PC1系統版本，ip資訊

[root@PC1 ~]# cat /etc/redhat-release   ## 檢視系統版本
Red Hat Enterprise Linux Server release 7.0 (Maipo)
[root@PC1 ~]# ifconfig | head -n 3  ## 檢視ip位址
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.10  netmask 255.255.255.255  broadcast 192.168.10.10
        inet6 fe80::20c:29ff:fe66:37f7  prefixlen 64  scopeid 0x20<link>

2、安裝DHCP服務（前提是已經配置好yum倉庫）

[root@PC1 ~]# yum install dhcp
Loaded plugins: langpacks, product-id, subscription-manager
Is this ok [y/d/N]: y
Downloading packages:
………………
Installed:
  dhcp.x86_64 12:4.2.5-27.el7                                                                          

Complete!

3、DHCP配置檔案位置

[root@PC1 dhcp]# pwd
/etc/dhcp
[root@PC1 dhcp]# ls
dhclient.d  dhcpd6.conf  dhcpd.conf

4、DHCP配置檔案中常見參數作用

5、修改配置檔案

[root@PC1 dhcp]# vim /etc/dhcp/dhcpd.conf   ## ip位址範圍為50-150
ddns-update-style none;
ignore client-updates;
subnet 192.168.10.0 netmask 255.255.255.0 {
range 192.168.10.50 192.168.10.150;
option subnet-mask 255.255.255.0;
option routers 192.168.10.1;
option domain-name "linuxprobe.com";
option domain-name-servers 192.168.10.1;
default-lease-time 21600;
max-lease-time 43200;
}

各參數意義：

6、重新開機伺服器PC1的DHCP服務，是配置檔案生效，并設定開機自動啟動服務

[root@PC1 dhcp]# systemctl restart dhcpd
[root@PC1 dhcp]# systemctl enable dhcpd
ln -s \'/usr/lib/systemd/system/dhcpd.service\' \'/etc/systemd/system/multi-user.target.wants/dhcpd.service\'

[root@PC1 dhcp]# systemctl status dhcpd | head -n 5  ## 檢視服務狀态
dhcpd.service - DHCPv4 Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; enabled)
   Active: active (running) since Wed 2020-12-02 18:47:16 CST; 2min 10s ago
     Docs: man:dhcpd(8)
           man:dhcpd.conf(5)

7、開啟客戶機PC2進行驗證

[root@PC2 Desktop]# ifconfig | head -n 3  ## 檢視目前ip，未配置設定
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 00:0c:29:25:bb:3e  txqueuelen 1000  (Ethernet)
        RX packets 22  bytes 1320 (1.2 KiB)
[root@PC2 Desktop]# vim /etc/sysconfig/network-scripts/ifcfg-eno16777728  ## 編輯網卡配置檔案，設為開機自動啟動
HWADDR=00:0C:29:25:BB:3E
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME=eno16777728
UUID=a0c2aa6b-48e1-4822-a67c-151155cc14bd
ONBOOT=yes
[root@PC2 Desktop]# systemctl restart network  ## 重新開機網卡
[root@PC2 Desktop]# ifconfig | head -n 3  ## 再次檢視ip
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.51  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe25:bb3e  prefixlen 64  scopeid 0x20<link>

8、開啟客戶機PC3進行驗證

[root@PC3 Desktop]# ifconfig | head -n 3  ## 檢視目前ip
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 00:0c:29:7d:e7:11  txqueuelen 1000  (Ethernet)
        RX packets 11  bytes 660 (660.0 B)
[root@PC3 Desktop]# vim /etc/sysconfig/network-scripts/ifcfg-eno16777728  ## 編輯網卡配置檔案，設為開機自動啟動
HWADDR=00:0C:29:7D:E7:11
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME=eno16777728
UUID=39fd8d2f-8276-4732-9207-1bf1942f91f9
ONBOOT=yes
[root@PC3 Desktop]# systemctl restart network  ## 重新開機網卡
[root@PC3 Desktop]# ifconfig | head -n 3  ## 檢視ip
eno16777728: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.52  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe7d:e711  prefixlen 64  scopeid 0x20<link>

總結：

伺服器與客戶機無需特殊處理，可以實作自動關聯
客戶機重新開機網卡，才可以實作自動被配置設定IP