Centos配置DHCP服务

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基础环境：

[root@PXE ~]# uname -a
Linux PXE 2.6.32-358.el6.x86_64 #1 SMP Fri Feb 22 00:31:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[root@PXE ~]# ifconfig 
eth0      Link encap:Ethernet  HWaddr 00:0C:29:70:00:DA  
          inet addr:1.1.1.13  Bcast:1.1.1.255  Mask:255.255.255.0
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0

[root@PXE ~]# uname -a

Linux PXE 2.6.32-358.el6.x86_64 #1 SMP Fri Feb 22 00:31:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

[root@PXE ~]# ifconfig

eth0 Link encap:Ethernet HWaddr 00:0C:29:70:00:DA

inet addr:1.1.1.13 Bcast:1.1.1.255 Mask:255.255.255.0

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

安装过程：

[root@PXE ~]# rpm -q dhcp
package dhcp is not installed
[root@PXE ~]# yum install dhcp

=====================================================================================================================================
 Package                        Arch                      Version                                      Repository               Size
=====================================================================================================================================
Installing:
 dhcp                           x86_64                    12:4.1.1-49.P1.el6.centos                    base                    822 k
Installing for dependencies:
 portreserve                    x86_64                    0.0.4-9.el6                                  base                     23 k
Updating for dependencies:
 dhclient                       x86_64                    12:4.1.1-49.P1.el6.centos                    base                    319 k
 dhcp-common                    x86_64                    12:4.1.1-49.P1.el6.centos                    base                    143 k

Transaction Summary
=====================================================================================================================================
Install       2 Package(s)
Upgrade       2 Package(s)
[root@PXE ~]# rpm -q dhcp    #检查dhcp是否安装    
dhcp-4.1.1-49.P1.el6.centos.x86_64
[root@PXE ~]# cp /etc/dhcp/dhcpd.conf /etc/dhcp/dhcpd.conf.$(date +%F)    #备份，其实没有内容，养成习惯很重要
################################默认################################
[root@PXE ~]# cp /usr/share/doc/dhcp-4.1.1/dhcpd.conf.sample /etc/dhcp/dhcpd.conf    #把模板拷贝过来
[root@PXE ~]# egrep -v "#" /etc/dhcp/dhcpd.conf
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

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



log-facility local7;


subnet 10.152.187.0 netmask 255.255.255.0 {
}


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;
}


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;
}

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;
}


host passacaglia {
  hardware ethernet 0:0:c0:5d:bd:95;
  filename "vmunix.passacaglia";
  server-name "toccata.fugue.com";
}

host fantasia {
  hardware ethernet 08:00:07:26:c0:a5;
  fixed-address fantasia.fugue.com;
}


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;
  }
}
################################默认################################
[root@PXE ~]# cat /etc/dhcp/dhcpd.conf
#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.sample
#   see 'man 5 dhcpd.conf'
#
default-lease-time 600;    #缺省租用时间
max-lease-time 7200;    #最大租用时间
ddns-update-style none;    #配置不使用DHCP-DNS动态更新模式，ddns-update-style interim;
    subnet 1.1.1.0 netmask 255.255.255.0 {    #作用域
        range dynamic-bootp 1.1.1.50 1.1.1.120;   #租用IP地址的范围 
        option routers 1.1.1.2;     #网关地址
        option subnet-mask 255.255.255.0;     #子网掩码
        filename "pxelinux.0";    #如果不是在TFTP根目录下，要写上目录
        next-server 1.1.1.13;    #tftp服务器地址
    }  
[root@PXE ~]# /etc/init.d/dhcpd start
Starting dhcpd:                                            [FAILED]
[root@PXE ~]# setenforce 0    #临时关闭selinux
[root@PXE ~]# /etc/init.d/dhcpd start
Starting dhcpd:                                            [  OK  ]
[root@PXE ~]# netstat -panu|grep dhc*  
udp        0      0 0.0.0.0:67                  0.0.0.0:*                               1445/dhcpd          
[root@PXE ~]# netstat -tunlp|grep dhc*
udp        0      0 0.0.0.0:67                  0.0.0.0:*                               1445/dhcpd 
[root@PXE ~]# /etc/init.d/iptables stop
or
[root@PXE ~]# -A INPUT -m state –state NEW -m udp -p udp –dport 67 -j ACCEPT
[root@PXE ~]# -A INPUT -m state –state NEW -m udp -p udp –dport 68 -j ACCEPT

[root@PXE ~]# cat /var/lib/dhcpd/dhcpd.leases
[root@PXE ~]# grep DHCPOFFER /var/log/messages
Jan 22 20:10:37 PXE dhcpd: DHCPOFFER on 1.1.1.50 to 00:0c:29:92:de:53 via eth0

[root@PXE ~]# cat /etc/sysconfig/dhcpd    #这个参数貌似没有关系。可以不修改
# Command line options here
DHCPDARGS=

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[root@PXE ~]# rpm -q dhcp

package dhcp is not installed

[root@PXE ~]# yum install dhcp

=====================================================================================================================================

Package Arch Version Repository Size

=====================================================================================================================================

Installing:

dhcp x86_64 12:4.1.1-49.P1.el6.centos base 822 k

Installing for dependencies:

portreserve x86_64 0.0.4-9.el6 base 23 k

Updating for dependencies:

dhclient x86_64 12:4.1.1-49.P1.el6.centos base 319 k

dhcp-common x86_64 12:4.1.1-49.P1.el6.centos base 143 k

Transaction Summary

=====================================================================================================================================

Install 2 Package(s)

Upgrade 2 Package(s)

[root@PXE ~]# rpm -q dhcp #检查dhcp是否安装

dhcp-4.1.1-49.P1.el6.centos.x86_64

[root@PXE ~]# cp /etc/dhcp/dhcpd.conf /etc/dhcp/dhcpd.conf.$(date +%F) #备份，其实没有内容，养成习惯很重要

################################默认################################

[root@PXE ~]# cp /usr/share/doc/dhcp-4.1.1/dhcpd.conf.sample /etc/dhcp/dhcpd.conf #把模板拷贝过来

[root@PXE ~]# egrep -v "#" /etc/dhcp/dhcpd.conf

option domain-name "example.org";

option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;

max-lease-time 7200;

log-facility local7;

subnet 10.152.187.0 netmask 255.255.255.0 {

}

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;

}

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;

}

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;

}

host passacaglia {

hardware ethernet 0:0:c0:5d:bd:95;

filename "vmunix.passacaglia";

server-name "toccata.fugue.com";

}

host fantasia {

hardware ethernet 08:00:07:26:c0:a5;

fixed-address fantasia.fugue.com;

}

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;

}

################################默认################################

[root@PXE ~]# cat /etc/dhcp/dhcpd.conf

# DHCP Server Configuration file.

# see /usr/share/doc/dhcp*/dhcpd.conf.sample

# see 'man 5 dhcpd.conf'

default-lease-time 600; #缺省租用时间

max-lease-time 7200; #最大租用时间

ddns-update-style none; #配置不使用DHCP-DNS动态更新模式，ddns-update-style interim;

subnet 1.1.1.0 netmask 255.255.255.0 { #作用域

range dynamic-bootp 1.1.1.50 1.1.1.120; #租用IP地址的范围

option routers 1.1.1.2; #网关地址

option subnet-mask 255.255.255.0; #子网掩码

filename "pxelinux.0"; #如果不是在TFTP根目录下，要写上目录

next-server 1.1.1.13; #tftp服务器地址

}

[root@PXE ~]# /etc/init.d/dhcpd start

Starting dhcpd: [FAILED]

[root@PXE ~]# setenforce 0 #临时关闭selinux

[root@PXE ~]# /etc/init.d/dhcpd start

Starting dhcpd: [ OK ]

[root@PXE ~]# netstat -panu|grep dhc*

udp 0 0 0.0.0.0:67 0.0.0.0:* 1445/dhcpd

[root@PXE ~]# netstat -tunlp|grep dhc*

udp 0 0 0.0.0.0:67 0.0.0.0:* 1445/dhcpd

[root@PXE ~]# /etc/init.d/iptables stop

[root@PXE ~]# -A INPUT -m state –state NEW -m udp -p udp –dport 67 -j ACCEPT

[root@PXE ~]# -A INPUT -m state –state NEW -m udp -p udp –dport 68 -j ACCEPT

[root@PXE ~]# cat /var/lib/dhcpd/dhcpd.leases

[root@PXE ~]# grep DHCPOFFER /var/log/messages

Jan 22 20:10:37 PXE dhcpd: DHCPOFFER on 1.1.1.50 to 00:0c:29:92:de:53 via eth0

[root@PXE ~]# cat /etc/sysconfig/dhcpd #这个参数貌似没有关系。可以不修改

# Command line options here

DHCPDARGS=

客户端：

[root@DHCP-client ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=yes
[root@DHCP-client ~]# ifconfig 
eth0      Link encap:Ethernet  HWaddr 00:0C:29:92:DE:53  
          inet addr:1.1.1.50  Bcast:1.1.1.255  Mask:255.255.255.0

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
[root@DHCP-client ~]# cat /var/lib/dhclient/dhclient-eth0.leases
lease {
  interface "eth0";
  fixed-address 1.1.1.50;
  filename "pxelinux.0";
  option subnet-mask 255.255.255.0;
  option routers 1.1.1.2;
  option dhcp-lease-time 600;
  option dhcp-message-type 5;
  option dhcp-server-identifier 1.1.1.13;
  renew 5 2016/01/22 12:15:36;
  rebind 5 2016/01/22 12:19:22;
  expire 5 2016/01/22 12:20:37;
}
lease {
  interface "eth0";
  fixed-address 1.1.1.50;
  filename "pxelinux.0";
  option subnet-mask 255.255.255.0;
  option routers 1.1.1.2;
  option dhcp-lease-time 600;
  option dhcp-message-type 5;
  option dhcp-server-identifier 1.1.1.13;
  renew 5 2016/01/22 12:20:30;
  rebind 5 2016/01/22 12:24:21;
  expire 5 2016/01/22 12:25:36;
}
[root@DHCP-client ~]#

[root@DHCP-client ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=yes

[root@DHCP-client ~]# ifconfig

eth0 Link encap:Ethernet HWaddr 00:0C:29:92:DE:53

inet addr:1.1.1.50 Bcast:1.1.1.255 Mask:255.255.255.0

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

[root@DHCP-client ~]# cat /var/lib/dhclient/dhclient-eth0.leases

lease {

interface "eth0";

fixed-address 1.1.1.50;

filename "pxelinux.0";

option subnet-mask 255.255.255.0;

option routers 1.1.1.2;

option dhcp-lease-time 600;

option dhcp-message-type 5;

option dhcp-server-identifier 1.1.1.13;

renew 5 2016/01/22 12:15:36;

rebind 5 2016/01/22 12:19:22;

expire 5 2016/01/22 12:20:37;

}

lease {

interface "eth0";

fixed-address 1.1.1.50;

filename "pxelinux.0";

option subnet-mask 255.255.255.0;

option routers 1.1.1.2;

option dhcp-lease-time 600;

option dhcp-message-type 5;

option dhcp-server-identifier 1.1.1.13;

renew 5 2016/01/22 12:20:30;

rebind 5 2016/01/22 12:24:21;

expire 5 2016/01/22 12:25:36;

}

[root@DHCP-client ~]#

dhcpd.conf配置文件的详细说明：
全局设置:

    ddns-update-style参数：设置DHCP服务器与DNS服务器的动态信息更新模式，一般的DHCP服务器可以不考虑设置该项，但是全局设置中一定要包括ddns-update-style的设置dhcpd才可以正常启动。设置为：interim 表示与DNS互动更新，设置为：none 表示不自动更新。
    default-lease-time参数：设置默认租约时间，参数值单位是秒。默认租约时间表示客户端从服务器租用一个IP地址的默认时间，到大时间后客户端会向服务器提出继续租用该IP地址的请求。
    max-lease-time参数：设置最大租约时间，参数值单位是秒。当客户端租约的地址到大这个时间，就不能继续租用该IP地址。
    option domain-name参数：设置主机所在域的名称，设置的域名和主机名称一起组成主机全名。
    option domain-name-servers参数：设置DNS服务器地址，设置后客户机DNS会使用该地址，如果要设置多个DNS地址，用逗号隔开。

ddns-update-style参数：设置DHCP服务器与DNS服务器的动态信息更新模式，一般的DHCP服务器可以不考虑设置该项，但是全局设置中一定要包括ddns-update-style的设置dhcpd才可以正常启动。设置为：interim 表示与DNS互动更新，设置为：none 表示不自动更新。

default-lease-time参数：设置默认租约时间，参数值单位是秒。默认租约时间表示客户端从服务器租用一个IP地址的默认时间，到大时间后客户端会向服务器提出继续租用该IP地址的请求。

max-lease-time参数：设置最大租约时间，参数值单位是秒。当客户端租约的地址到大这个时间，就不能继续租用该IP地址。

option domain-name参数：设置主机所在域的名称，设置的域名和主机名称一起组成主机全名。

option domain-name-servers参数：设置DNS服务器地址，设置后客户机DNS会使用该地址，如果要设置多个DNS地址，用逗号隔开。

使用subnet声明设置子网属性:

    subnet后面设置网络地址，netmask后面设置子网掩码。
    range参数：是设置subnet中可供动态分配的IP地址范围，参数值一定要是subnet设置的子网之内，否则不能启动。
    subnet-mask参数：设置子网掩码，设置子网掩码之后一般不需要再设置网络地址和广播地址。
    routers参数：是设置默认网关。

subnet后面设置网络地址，netmask后面设置子网掩码。

range参数：是设置subnet中可供动态分配的IP地址范围，参数值一定要是subnet设置的子网之内，否则不能启动。

subnet-mask参数：设置子网掩码，设置子网掩码之后一般不需要再设置网络地址和广播地址。

routers参数：是设置默认网关。

使用host声明设置主机属性，通常用于为服务器分配好固定使用的IP地址:

    host后面需要为DHCP客户端主机设置主机名称。
    hardware参数：是设置客户端主机的物理地址（MAC地址），因为通常使用的都是以太网，所以hardware参数类型设置为ethernet。
    fixed-address参数：设置在host声明中指定的客户端分配固定使用的IP地址。

host后面需要为DHCP客户端主机设置主机名称。

hardware参数：是设置客户端主机的物理地址（MAC地址），因为通常使用的都是以太网，所以hardware参数类型设置为ethernet。

fixed-address参数：设置在host声明中指定的客户端分配固定使用的IP地址。

参考资料：https://www.isc.org/downloads/dhcp/
参数转载：http://www.centoscn.com/image-text/config/2015/0420/5219.html SourceByrd's Weblog-https://note.t4x.org/basic/centos-config-dhcp/

申明：除非注明Byrd's Blog内容均为原创,未经许可禁止转载!详情请阅读版权申明!