DHCP Configuration fixed IP

DHCP (Dynamic Host Configuration Protocol) is commonly used in large local network environment, the main role is centralized management, assigning IP address, so that the host in the network environment to obtain the dynamic IP address, gateway address , DNS server address and other information, and can increase the usage of the address.

C/S mode

Server:dhcp Server (running DHCP Service) UDP service: 67

Client:dhcp Client (running DHCP program) UDP service: 68

UDP: Suitable for sending smaller data messages, and high timeliness requirements

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When the client gets a valid address, DHCP sends a 169.254.x.x as the local address

Installation configuration:

[[email protected] ~]# Yum install DHCP

Configuration file :

[Email protected] dhcp]# pwd/etc/dhcp[[email protected] dhcp]# cp/usr/share/doc/dhcp-4.1.1/dhcpd.conf.sample Dhcpd.conf

configuration file Description:

[[email protected] dhcp]# vim dhcpd.conf#log-facility local7;  #日志/var/log/ boot.log  #全局地址分配属性: Option starts #option domain-name                      #域名搜索列表, similar to the searchoption in/etc/resolv.conf   #domain-name-servers             # Name server address, multiple words separated by commas #option routers                            #网关 #option  broadcasst-address               # Broadcast Address #option subnet-mask                        #子网掩码 #default-lease-time                           #默认租约期限, generally this entry takes effect (in seconds) # max-lease-time                                #最大租约期限 (in seconds)      #range   START_IP END_IP                 #地址池 (You can specify more than one range in subnet, but multiple ranges define an IP range that cannot be duplicated) #子网配置: typically each scope is defined by a subnet #subnet  network_addr netmask netmask {#range   #option  routers #}# Host configuration: Usually fixed for a specific MAC address assigned an address #host  ' Host id '  {#hardware  ethernet 08:00:07:26:c0:a5;# fixed-address ip;#}

service process:

[[email protected] ~]# /etc/init.d/dhcpd  restartshutting down dhcpd:                                          [  OK  ]Starting dhcpd:                                              [   OK  ][[email protected] ~]# ps -ef |grep dhcpdhcpd       1952      1  0 03:53 ?         00:00:00 /usr/sbin/dhcpd -user dhcpd -group  dhcpd

Service Port:

[[email protected] ~]# ss -lnupstate       recv-q  send-q                                      Local Address:Port                                        Peer Address:Port UNCONN       0      0                                                        *:67                                                     *:*       users: (("DHCPD", 1952,7)) unconn      0       0                                                        *:68                                                     *:*        users: (("Dhclient", 2066,6))

Demo

[[email protected] dhcp]# VIM dhcpd.conf# global variable option domain-name "Marvin"; option Domain-name-servers 114.114.114.114,8.8.8.8;option Routers 192.168.1.1;option broadcast-address 192.168.1.255;default-lease-time 600; Max-lease-time 7200;log-facility local7;subnet 192.168.1.0 netmask 255.255.255.0{range 192.168.1.201 192.168.1.240;  Host sherry{# based on host MAC configuration fixed IP hardware Ethernet 00:0c:29:3c:e2:60; #sherry主机的mac地址 fixed-address 192.168.1.221; #给sherry主机分配固定ip}}

Log

service error:

[[email protected] /]# tail  -f /var/log/messages may 19 06:24:47  marvin dhcpd: Dynamic and static leases present for  192.168.1.221.may 19 06:24:47 marvin dhcpd: remove host declaration  sherry or remove 192.168.1.221may 19 06:24:47 marvin dhcpd: from  The dynamic address pool for 192.168.1.0/24may 19 06:24:47 marvin  dhcpd: DHCPREQUEST for 192.168.1.221 from 00:0c:29:3c:e2:60 via  eth1may 19 06:24:47 marvin dhcpd: dhcpack on 192.168.1.221 to  00:0c:29:3c:e2:60 via eth1may 19 06:29:43 marvin dhcpd: dynamic and  static leases present for 192.168.1.221.May 19 06:29:43 marvin  Dhcpd: remove host declaration sherry or remove 192.168.1.221may 19 06:29:43 marvin dhcpd:  from the dynamic address pool for 192.168.1.0/24may 19 06:29:43  Marvin dhcpd: dhcprequest for 192.168.1.221 from 00:0c:29:3c:e2:60 via  eth1may 19 06:29:43 marvin dhcpd: dhcpack on 192.168.1.221 to  00:0c:29:3c:e2:60 via eth1

Service log:

[[email protected] /]# tail -f /var/log/boot.log may 19 06:24:47  Marvin dhcpd: dynamic and static leases present for 192.168.1.221.may  19 06:24:47 marvin dhcpd: remove host declaration sherry or  remove 192.168.1.221May 19 06:24:47 marvin dhcpd: from the  DYNAMIC ADDRESS POOL FOR 192.168.1.0/24MAY 19 06:24:47 MARVIN DHCPD:  dhcprequest for 192.168.1.221 from 00:0c:29:3c:e2:60 via eth1may 19  06:24:47 marvin dhcpd: dhcpack on 192.168.1.221 to 00:0c:29:3c:e2:60  via eth1May 19 06:29:43 marvin dhcpd: Dynamic and static  Leases present for 192.168.1.221.may 19 06:29:43 marvin dhcpd: remove  host declaration&nBsp;sherry or remove 192.168.1.221may 19 06:29:43 marvin dhcpd: from  the dynamic address pool for 192.168.1.0/24May 19 06:29:43  Marvin dhcpd: dhcprequest for 192.168.1.221 from 00:0c:29:3c:e2:60 via  eth1may 19 06:29:43 marvin dhcpd: dhcpack on 192.168.1.221 to  00:0c:29:3c:e2:60 via eth1

DHCP Configuration fixed IP