linux-dhcp relay-020

 Dhcp中继

 

配置运行环境

1.       DHCP server  在Linux 192.168.10.100上

2.       router        在linux上配置relay

3.       区域192.168.20.x 192.168.30.x通过router向DHCP server申请地址

 

l         Linux中必须做Dhcp服务器的作用域,即服务器必须在作用域中,可以是空作用域

 

1.安装dhcp server

[root@localhost Server]# rpm -qa dhcp

dhcp- 3.0.5 -18.el5.i386.rpm            dhcpv6-1.0.10-16.el5.i386.rpm        

dhcp-devel- 3.0.5 -18.el5.i386.rpm      dhcpv6-client-1.0.10-16.el5.i386.rpm 

[root@localhost Server]# rpm -qa dhcp

[root@localhost Server]#

[root@localhost Server]# rpm -ivh dhcp- 3.0.5 -18.el5.i386.rpm

 

 

2.配置dhcpd.conf文件

[root@localhost ~]# vim /etc/dhcpd.conf

ddns-update-style interim;

ignore client-updates;

#定义区域192.168.20.0

subnet 192.168.20.0 netmask 255.255.255.0 {

        option routers                  192.168.20.254;--设置客户端的默认网关

        option subnet-mask              255.255.255.0;

        range dynamic-bootp 192.168.20.1 192.168.20.10;

        default-lease-time 21600;

        max-lease-time 43200;

}

#定义区域192.168.30.0

subnet 192.168.30.0 netmask 255.255.255.0 {

 

        option routers                  192.168.30.254;

        option subnet-mask              255.255.255.0;

        range dynamic-bootp 192.168.30.1 192.168.30.10;

        default-lease-time 21600;

        max-lease-time 43200;

}

#定义区域192.168.10.0 dhcp server所在的区域，可以是空区域

subnet 192.168.10.0 netmask 255.255.255.0 {

} 

#定义配置信息的参考模板可以从下面的文件读入    

:r /usr/share/doc/dhcp- 3.0.5 /dhcpd.conf.sample

#检查配置信息是否有错

[root@localhost ~]# service dhcpd configtest

Syntax: OK

 

 

3.配置server的ip

[root@localhost Server] vim /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

BOOTPROTO=none

IPADDR=192.168.10.100

NETWORK=255.255.255.0

GATEWAY=192.168.10.254

ONBOOT=yes

HWADDR=00:0c:29:7d:c7:28

[root@localhost Server]# service network restart.

 

4.启动dhcpd

[root@localhost ~]# chkconfig --list dhcpd

dhcpd           0:off   1:off   2:off   3:off   4:off   5:off   6:off

[root@localhost ~]# chkconfig  dhcpd on

[root@localhost ~]# chkconfig --list dhcpd

dhcpd           0:off   1:off   2:on    3:on    4:on    5:on    6:off

 

5.查看server的路由

[root@localhost ~]# route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

192.168.10.0    0.0.0 .0         255.255.255.0   U     0      0        0 eth0

169.254.0.0     0.0.0 .0         255.255.0.0     U     0      0        0 eth0

0.0.0 .0         192.168.10.254  0.0.0.0         UG    0      0        0 eth0

[root@localhost ~]#

 

6.测试到达路由是否联通

[root@localhost ~]# ping 192.168.10.254

PING 192.168.10.254 (192.168.10.254) 56(84) bytes of data.

64 bytes from 192.168.10.254: icmp_seq=1 ttl=128 time=0.304 ms

[root@localhost ~]# ping 192.168.20.254

PING 192.168.20.254 (192.168.20.254) 56(84) bytes of data.

64 bytes from 192.168.20.254: icmp_seq=1 ttl=128 time=0.460 ms

[root@localhost ~]# ping 192.168.30.254

PING 192.168.30.254 (192.168.30.254) 56(84) bytes of data.

64 bytes from 192.168.30.254: icmp_seq=1 ttl=128 time=0.177 ms

[root@localhost ~]#

 

l         配置Linux relay 

dhcrelay包含在dhcp- 3.0.5 -18.el5.i386.rpm

 

1.       安装dhcp server

[root@localhost Server]# rpm -qa dhcp

dhcp- 3.0.5 -18.el5.i386.rpm            dhcpv6-1.0.10-16.el5.i386.rpm        

dhcp-devel- 3.0.5 -18.el5.i386.rpm      dhcpv6-client-1.0.10-16.el5.i386.rpm 

[root@localhost Server]# rpm -qa dhcp

[root@localhost Server]#

[root@localhost Server]# rpm -ivh dhcp- 3.0.5 -18.el5.i386.rpm

2.配置dhcrelay文件

#查看dhcp安装包含的文件—包含dhcrelay

[root@localhost ~]# rpm -ql dhcp

/etc/dhcpd.conf

/etc/rc.d/init.d/dhcpd

/etc/rc.d/init.d/dhcrelay

/etc/sysconfig/dhcpd

/etc/sysconfig/dhcrelay

[root@localhost ~]# vim /etc/sysconfig/dhcrelay

INTERFACES="eth0 eth1 eth2"

DHCPSERVERS="192.168.10.100"

#netstat –tulpn |grep dhc

3.开启路由功能                                                                     

[root@localhost ~]# vim /etc/sysctl.conf

--开启路由

net.ipv4.ip_forward = 1

--同步信息

[root@localhost ~]# sysctl -p

net.ipv4.ip_forward = 1

net.ipv4.conf.default.rp_filter = 1

net.ipv4.conf.default.accept_source_route = 0

kernel.sysrq = 0

kernel.core_uses_pid = 1

net.ipv4.tcp_syncookies = 1

kernel.msgmnb = 65536

kernel.msgmax = 65536

kernel.shmmax = 4294967295

kernel.shmall = 268435456

4.关闭DHCP服务，开启DHCP中继服务

[root@localhost ~]# chkconfig --list |grep dhc

dhcpd            0:off       1:off       2:on 3:on 4:on 5:on 6:off

dhcrelay           0:off       1:off       2:off       3:off       4:off       5:off       6:off

[root@localhost ~]# chkconfig  dhcpd off

 [root@localhost ~]# chkconfig  dhcrelay on

[root@localhost ~]# chkconfig --list |grep dhc

dhcpd            0:off       1:off       2:off       3:off       4:off       5:off       6:off

dhcrelay           0:off       1:off       2:on 3:on 4:on 5:on 6:off

5.如果客户端分配不到ip

[root@localhost ~]#service dhcrelay start

6．查看DHCP中继路由

[root@localhost ~]# route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

192.168.20.0    0.0.0 .0         255.255.255.0   U     0      0        0 eth1

192.168.30.0    0.0.0 .0         255.255.255.0   U     0      0        0 eth2

192.168.10.0    0.0.0 .0         255.255.255.0   U     0      0        0 eth0

169.254.0.0     0.0.0 .0         255.255.0.0     U     0      0        0 eth2

[root@localhost ~]# 

l         客户端获取地址

windows xp 和linux分别在vm3 vm2 获取地址

Vm2

 

Vm3