Centos7 搭建DHCP Server
DHCP 埠號查詢
[[email protected] /]# vim /etc/services
輸入/dhcp 快速查詢關鍵字
DHCP協議互動過程
1)DHCP DISCOVER(0x01),此為Client廣播尋找可用DHCP Server的過程
2)DHCP OFFER(0x02),此為Server對DHCP DISCOVER報文的響應,並向Client提供配置引數等資訊
3)DHCP REQUEST(0x03),此報文是Client對server的DHCP OFFER報文的迴應,或者是Client續延IP地址租期時發出的報文
4)DHCP DECLINE(0x04),當Client發現Server分配給它的IP地址無法使用,如IP地址衝突時,將發出此報文,通知Server禁止使用IP地址
5)DHCP ACK(0x05),Server對Client的DHCP REQUEST報文的確認響應報文,Client收到此報文後,才真正獲得了IP地址和相關的配置資訊。
6)DHCP NAK(0x06),Server對Client的DHCP REQUEST報文的拒絕響應報文,Client收到此報文後,一般會重新開始新的DHCP過程。
7)DHCP RELEASE(0x07),Client主動釋放server分配給它的IP地址的報文,當Server收到此報文後,就可以回收這個IP地址,能夠分配給其他的Client。
8)DHCP INFORM(0x08),Client已經獲得了IP地址,傳送此報文,只是為了從DHCP SERVER處獲取其他的一些網路配置資訊,如route ip,DNS Ip等,這種報文的應用非常少見。
如:執行IPCONFIG/RELEASE後,PC會發出釋放IP的報文,DHCP Message Type是7,他的作用是主動釋放server分配給它的IP地址的報文,Server收到此報文後,就可以回收這個IP地址,能夠分配給其他的Client。
安裝DHCP 服務操作步驟:
Dhcp 配置檔案
[[email protected] xlxh]# ls /etc/dhcp/
dhclient.d dhclient-exit-hooks.d dhcpd6.conf dhcpd.conf scripts
發現dhcpd.conf是一個空檔案,需要參照/usr/share/doc/dhcp-4.2.5/dhcpd.conf.example
[[email protected] doc]# cat dhc
dhclient-4.2.5/ dhcp-4.2.5/ dhcp-common-4.2.5/
[ [email protected] doc]# pwd
/usr/share/doc
[[email protected] doc]#
將範本拷貝到/etc/dhcp/目錄下替換dhcpd.conf
[[email protected] dhcp]# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf
cp: overwrite ‘/etc/dhcp/dhcpd.conf’? y
[[email protected] dhcp]#
[[email protected] dhcp]# /etc/init.d/dhcpd restart
[ [email protected] dhcp]# service dhcpd restart
Redirecting to /bin/systemctl restart dhcpd.service
Job for dhcpd.service failed because the control process exited with error code. See "systemctl status dhcpd.service" and "journalctl -xe" for details.
[[email protected] dhcp]#
[[email protected] dhcp]# chkconfig dhcpd on
[[email protected] dhcp]# chkconfig --list dhcpd
開機自啟動
systemctl restart dhcpd.service
systemctl status dhcpd
實戰操作
公司有60臺電腦,IP地址:192.168.1.2-192.168.1.250,子網掩碼24,閘道器為192.18.1.1.
進入[[email protected] xlxh]# vim /etc/dhcp/dhcpd.conf修改配置
#A slightly different configuration for an internal subnet.
subnet 10.10.20.0 netmask 255.255.255.0 {
#DHCP Server config
range 10.10.20.100 10.10.20.200;
option domain-name-servers 10.10.20.254;
option domain-name "internal.example.org";
option routers 10.10.20.254;
option broadcast-address 10.10.20.255;
default-lease-time 600;
max-lease-time 7200;
#fix IP assign to PC 指定某臺電腦分配IP地址
host xxx{
hardware ethernet xx:xx:xx:xx:xx;
fixed-address 10.10.20.100;
}
}
如:PC連線DHCP Server後檢視PC是否能動態獲取IP地址
C:\Users\xlxh>hostname
xlxh-PC
C:\Users\xlxh>ipconfig /all
乙太網介面卡 本地連線:
連線特定的 DNS 字尾 . . . . . . . :
描述. . . . . . . . . . . . . . . : Realtek PCIe GBE Family Controller
實體地址. . . . . . . . . . . . . : 2C:60:0C:1C:93:28
DHCP 已啟用 . . . . . . . . . . . : 是
自動配置已啟用. . . . . . . . . . : 是