【08-04】搭建dhcp服务，实现ip地址申请分发

搭建dhcp服务，实现ip地址申请分发

 

0.环境准备

思路：两台设备 一台作为dhcp服务器下发地址，一台接收，如果接收的地址是设定网段的话则为成功，并通过看分发记录，对比MAC地址来确保下发成功。

需要先在VMware中关闭DHCP功能：

　　编辑->虚拟网络编辑器->更改设置->仅主机模式->取消勾选：使用本地DHCP服务器将IP地址分配给虚拟机

 

1.安装dhcp服务

#CentOS7之前安装dhcp 8安装dhcp-server
[root@Rocky8-1 ~]# yum install -y dhcp-server 

2.配置DHCP服务

#查看配置文件发现什么都没有
[root@Rocky8-1 ~]# vim /etc/dhcp/dhcpd.conf   
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp-server/dhcpd.conf.example     
#   see dhcpd.conf(5) man page
​
#如果想要了解则导入引导文件到配置文件中
[root@Rocky8-1 ~]# cat /usr/share/doc/dhcp-server/dhcpd.conf.example >> /etc/dhcp/dhcpd.conf 
​
​
#但是我没用配置 我这里使用的是最简单的配置
[root@Rocky8-1 ~]# vim /etc/dhcp/dhcpd.conf          
option domain-name-servers 114.114.114.114, 8.8.8.8;
​
default-lease-time 86400; #默认租约时间 一天86400
max-lease-time 106400;
log-facility local7;
​
subnet 10.0.0.0 netmask 255.255.255.0 {
        range 10.0.0.200 10.0.0.220;
        option routers 10.0.0.2;
}

 

3.启动DHCP服务

#因为是实验所以没开开机启动
[root@Rocky8-1 ~]# systemctl restart dhcpd
[root@Rocky8-1 ~]# systemctl status dhcpd
● dhcpd.service - DHCPv4 Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled; vendor preset: disabled)
   Active: active (running) since Wed 2022-03-23 23:53:55 CST; 2s ago
     Docs: man:dhcpd(8)
           man:dhcpd.conf(5)
 Main PID: 2523 (dhcpd)
   Status: "Dispatching packets..."
    Tasks: 1 (limit: 2565)
   Memory: 4.8M
   CGroup: /system.slice/dhcpd.service
           └─2523 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid
​
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Copyright 2004-2017 Internet Systems Consortium.
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: All rights reserved.
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: For info, please visit https://www.isc.org/software/dhcp/
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Source compiled to use binary-leases
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Wrote 0 leases to leases file.
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Listening on LPF/eth0/00:0c:29:58:fe:9a/10.0.0.0/24
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Sending on   LPF/eth0/00:0c:29:58:fe:9a/10.0.0.0/24
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Sending on   Socket/fallback/fallback-net
3月 23 23:53:55 Rocky8-1 dhcpd[2523]: Server starting service.
3月 23 23:53:55 Rocky8-1 systemd[1]: Started DHCPv4 Server Daemon.

 

4.验证结果

#查看DHCP的分发信息
[root@Rocky8-1 ~]# vim /var/lib/dhcpd/dhcpd.leases
​
# The format of this file is documented in the dhcpd.leases(5) manual page.
# This lease file was written by isc-dhcp-4.3.6
​
# authoring-byte-order entry is generated, DO NOT DELETE
authoring-byte-order little-endian;
​
server-duid "\000\001\000\001)\315\374b\000\014)X\376\232";
​
lease 10.0.0.200 {
  starts 3 2022/03/23 16:03:04;
  ends 4 2022/03/24 16:03:04;
  cltt 3 2022/03/23 16:03:04;
  binding state active;
  next binding state free;
  rewind binding state free;
  hardware ethernet 00:0c:29:6f:d5:df;
  uid "\001\000\014)o\325\337";
  client-hostname "Rocky8-2";
}
=====================================================================================================
# 查看接收端IP地址和MAC地址进行对比
[root@Rocky8-2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:6f:d5:df brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.200/8 brd 10.255.255.255 scope global dynamic noprefixroute eth0
       valid_lft 1741sec preferred_lft 1741sec
    inet6 fe80::20c:29ff:fe6f:d5df/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

实验成功

 

5.配置文件详解

[root@Rocky8-1 ~]# vim /etc/dhcp/dhcpd.conf 
​
# Sample configuration file for ISC dhcpd
#  ISC dhcpd的示例配置文件
​
# option definitions common to all supported networks...
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;   #默认DNS
​
#默认租约时间 一天86400
default-lease-time 600;
#最大租约时间 106400
max-lease-time 7200;
​
#是否开启全局动态dns更新
# Use this to enble / disable dynamic dns updates globally.
#ddns-update-style none;
​
# 如果这是权威dhcp服务器则关闭注释
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;
​
#日志文件储存位置
# Use this to send dhcp log messages to a different log file (you also
# have to hack syslog.conf to complete the redirection).
log-facility local7;
​
#此处不提供服务器，声明后有助于DHCP服务器了解网络拓扑
# No service will be given on this subnet, but declaring it helps the 
# DHCP server to understand the network topology.
subnet 10.152.187.0 netmask 255.255.255.0 {
}
​
#基本网络声明
# This is a very basic subnet declaration.
subnet 10.254.239.0 netmask 255.255.255.224 {
  range 10.254.239.10 10.254.239.20;         #dhcp范围
  option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;   #网关
}
​
#此处语序BOOTP客户端获取动态地址，不推荐
# This declaration allows BOOTP clients to get dynamic addresses,
# which we don't really recommend.
subnet 10.254.239.32 netmask 255.255.255.224 {
  range dynamic-bootp 10.254.239.40 10.254.239.60;
  option broadcast-address 10.254.239.31;
  option routers rtr-239-32-1.example.org;
}
​
#内部子网配置略有不同
# A slightly different configuration for an internal subnet.
subnet 10.5.5.0 netmask 255.255.255.224 {
  range 10.5.5.26 10.5.5.30;
  option domain-name-servers ns1.internal.example.org;
  option domain-name "internal.example.org";
  option routers 10.5.5.1;
  option broadcast-address 10.5.5.31;
  default-lease-time 600;
  max-lease-time 7200;
​
}
​
# 需要特殊配置选项的主机可以在主机语句中列出。如果没有指定地址，则地址将被动态分配（如果可能），但主机特定信息仍将来自主机声明。
# Hosts which require special configuration options can be listed in
# host statements.   If no address is specified, the address will be
# allocated dynamically (if possible), but the host-specific information
# will still come from the host declaration.
host passacaglia {
  hardware ethernet 0:0:c0:5d:bd:95;
  next-server:10.0.0.8                #下载服务器使用TFTP服务地址
  filename "pexlinux.0";              #读取的文件内容
  server-name "toccata.example.com";
}
​
#根据Mac地址分发地址，如果没有硬件地址则根据DHCP分发地址
# Fixed IP addresses can also be specified for hosts.   These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP.   Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.
host fantasia {
  hardware ethernet 08:00:07:26:c0:a5;
  fixed-address fantasia.example.com;
}
​
#根据客户端下发地址
# You can declare a class of clients and then do address allocation
# based on that.   The example below shows a case where all clients
# in a certain class get addresses on the 10.17.224/24 subnet, and all
# other clients get addresses on the 10.0.29/24 subnet.
class "foo" {
  match if substring (option vendor-class-identifier, 0, 4) = "SUNW";
}
​
shared-network 224-29 {
  subnet 10.17.224.0 netmask 255.255.255.0 {
    option routers rtr-224.example.org;
  }
  subnet 10.0.29.0 netmask 255.255.255.0 {
    option routers rtr-29.example.org;
  }
  pool {
    allow members of "foo";
    range 10.17.224.10 10.17.224.250;
  }
  pool {
    deny members of "foo";
    range 10.0.29.10 10.0.29.230;
  }
}