linux[Base]-34-[DHCP Server]-[Dynamic Host Management Protocol]-[01]

Dhcp

DHCP Dynamic Host Management protocol based on UDP Protocol and limited to network protocol for LAN

Purpose: Automatic distribution for internal network devices or Internet providers IP Address

Typically applied in a large LAN environment

Benefits: Centralized Management IP addresses to reduce management and maintenance costs and increase efficiency

Common terminology for DHCP service programs:

scope: A complete IP address segment,DHCP manages assigning IP addresses according to scope

superscope: Used to support multiple logic on the same physical network IP Address subnet segment, containing a list of scopes, including management of child scopes

Exclusion Range: set some IP addresses are excluded from the scope and are not obtained by the DHCP client

address pool: Defines a DHCP scope and applies an excluded address to be assigned to the DHCP client

Lease:DHCP client gets IP address usage time

Appointment: Ensure that specific devices in the subnet are always getting the same IP Address

Install the DHCPD service program:

[[email protected] ~]# yum-y Install DHCP

DHCPD Service Program and configuration file :

Master configuration file	/etc/dhcp/dhcpd.conf
Execute the program	/usr/sbin/dhcpd /usr/sbin/dhcrelay

a standard DHCP configuration file should include global configuration parameters, subnet segment declarations, address configuration options, address configuration parameters

Global configuration parameters are used to define global parameters for the entire configuration file, while the subnet segment declaration is used to configure the address properties of the entire subnet segment

Parameters	Role
Ddns-update-style Type	Defines the type of dynamic update for the DNS service, including: None(dynamic update not supported),intermi(interactive update mode),Ad-hoc(Special update mode)
Allow/ignore client-updates	Allow / Ignore client update DNS records
Default-lease-time 21600	Default Time-out
Max-lease-time 43200	Maximum timeout time
Option Domain-name-server Ip-addres	Define DHS server addresses
option Domain-name " name "	Define DHS domain names
Range	Define an address pool for assigning IP
Option Subnet-mask	Defining subnet masks for clients
Option routers	Define the gateway for the client
Broadcase-address Broadcast Address	Define the broadcast address of the client
Ntp-servers IP Address	Define the client's network time server (NTP)
Nis-servers IP Address	Define the address of the NIS domain server
Hardware hardware type MAC is in a hurry!	Specify the type of NIC interface and mac address
Server-name Host name	Notifies the DHCP client server of the host name
Fixed-address IP Address	Assigning a fixed IP address to a specified host
Time-offset Offset Difference	Specify the offset difference between the client and Greenwich

Simulation Experiment :

tomorrow, there are about six external colleges bring their own notebooks to our training, please ensure that students can correctly obtain IP address and normal Internet access

The computer room network segment parameters are as follows:

Parameter name	Value
Default Lease Time	21600
Maximum lease time	43200
IP address range	192.168.200.20-192.168.200.100
Subnet mask	255.255.255.0
Gateway	192.168.200.1
DNS Server Address	192.168.200.103
Search domain	Linuxs.com

To configure a DHCP configuration file:

[Email protected] ~]# vim/etc/dhcp/Dhcpd.confddns-update-style none; #设置dhcp服务不自动动态更新Ignore client-updates; #忽略客户机更新dns记录Subnet192.168.200.0Netmask255.255.255.0{#作用域为 192.168.200.0/ 24 Network segment range192.168.200.20 192.168.200.100;#地址池: 20-100option Subnet-mask255.255.255.0;#子网掩码:option Routers192.168.200.1;#网关: 192.168.200.1option Domain-name"linuxs.com"; #默认搜索域option domain-name-servers192.168.200.103; #dns地址default-lease-time21600; #默认租约Max-lease-time43200; #最大租约Host Print {hardware Ethernetxx: 0C: in: FC:FF:B8; #绑定MAC地址
　　　　　　　　fixed-address192.168.200.88; #静态IP地址}}

Restart DHCPD service Verification :

[Email protected] ~~'/usr/lib/systemd/system/dhcpd.service' ' /etc/systemd/system/multi-user.target.wants/dhcpd.service '

　　

linux[Base]-34-[DHCP Server]-[Dynamic Host Management Protocol]-[01]