本次实验采用CentOS7

1.检查

在安装DHCP之前先使用rpm命令查看系统中已有的DHCP软件包

rpm -qa | grep dhcp

由此可知，系统中尚未安装DHCP软件包

2.安装

我们可以使用yum命令为系统安装DHCP软件包

yum -y install dhcp

安装完成后再次检查可以看到DHCP软件包

3.配置dhcp配置文件

我们在上面的安装过程中已经知道了当前系统中的dhcp软件包版本为 4.2.5

因此去往路径/usr/share/doc/dhcp-4.2.5/dhcpd.conf.example

---

这里是一些介绍，想要直接配置的可以跳过

# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#

# option definitions common to all supported networks...
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

# Use this to enble / disable dynamic dns updates globally.
#ddns-update-style none;

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;

# 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;

# 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 {
}

# 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;
  option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;
}

# 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;
}

# 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;
}

# 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;
  filename "vmunix.passacaglia";
  server-name "toccata.fugue.com";
}
                                                                                                  1,1          顶端

# 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.fugue.com;
}

# 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;
  }
}
                                                                                                    100,1        底端

DHCP服务参数

DHCP服务声明

DHCP服务选项

---

简单的编写一个配置文件

allow booting;
#分配子网，网段为192.168.138.0 子网掩码为255.255.255.0
subnet 192.168.138.0 netmask 255.255.255.0 {
    range 192.168.138.128 192.168.138.254; #设置子网的IP地址取值范围
    #设置为客户端分配的DNS服务器地址
    option domain-name-servers 192.168.138.2;
    #设置客户端的DNS域名
    option domain-name "internal.example.org";
    #设置网关地址
    option routers 192.168.138.2;
    #设置最短租约时常
    default-lease-time 3600;
    #设置最长租约时长
    max-lease-time 7200;
    #设置文件共享服务器地址
    next-server 192.168.138.9
    #设置文件服务器上共享的启动文件名称
    filename "pxelinux.0"
}

需要注意:

1.在格式上配置文件应该与模板中提供的格式相同

2.在内容上，地址池的IP地址范围应该在子网范围内，本机网卡IP应在地址池范围之内

所有配置完成之后，在客户端上将网卡的配置文件中的BOOTPROTO项的值设为dhcp

再重启网络服务即可