路由器上实现DHCP和DHCP中继

申明：本文为“老毛”原创，如需转载，请与作者联系。否则将视为侵权行为，作者将追究其法律责任。

 

环境如下：其中最左边的ROUTER模拟PC,中间的ROUTER做代理服务器，最后一台做DHCP服务器

目标：PC上能自动获得IP地址

 

1，pc上的配置

en

conf t

host pc

inter f0/0

ip add dhcp              ip地址为从DHCP获取

no shut

 

以下是show run看到的

pc#show run
Building configuration...

Current configuration : 887 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname pc
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
no ip routing
!
!
no ip cef
!
!
!
!        
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 ip address dhcp
 no ip route-cache
 duplex half
!
interface FastEthernet1/0
 no ip address
 no ip route-cache
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet1/1
 no ip address
 no ip route-cache
 shutdown
 duplex auto
 speed auto
!
ip classless
no ip http server
!
!
!
!
!
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 logging synchronous
 transport preferred all
 transport output all
 stopbits 1
line aux 0
 transport preferred all
 transport output all
 stopbits 1
line vty 0 4
 login
 transport preferred all
 transport input all
 transport output all
!
!
end

 

 

2，router的配置

en

conf t

inter f0/0

ip add 1.1.1.1 255.255.255.0

no shut

ip helper-address 2.2.2.2             监听放F0/0上的udp广播，并转发到2.2.2.2上

inter f1/1

ip add 2.2.2.1 255.255.255.0

no shut

exit

router eigrp 1                                做EIGRP路由，否则路由表为空，两边无法连通

network 1.1.1.0

network 2.2.2.0

no auto-su                                    关闭路由汇总

 

以下是show run看到的

show run
Building configuration...

Current configuration : 981 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
!
!
ip cef
ip dhcp excluded-address 1.1.1.1 1.1.1.100
!
!
!
!        
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 1.1.1.1 255.255.255.0
 ip helper-address 2.2.2.2
 duplex half
!
interface FastEthernet1/0
 no ip address
 shutdown
 duplex auto
 speed auto
!        
interface FastEthernet1/1
 ip address 2.2.2.1 255.255.255.0
 duplex auto
 speed auto
!
router eigrp 1
 network 1.0.0.0
 network 2.0.0.0
 no auto-summary
!
ip classless
no ip http server
!
!
!
!
!
!
!
!
gatekeeper
 shutdown
!        
!
line con 0
 exec-timeout 0 0
 logging synchronous
 transport preferred all
 transport output all
 stopbits 1
line aux 0
 transport preferred all
 transport output all
 stopbits 1
line vty 0 4
 login
 transport preferred all
 transport input all
 transport output all
!
!
end

 

3，DHCP上的配置

en

conf t

host dhcp

router eigrp 1

net 2.2.2.0

no auto

exit

inter f1/1

ip add 2.2.2.2 255.255.255.0

no shut

exit

 ip dhcp pool test              定义一个地址池叫test

network 1.1.1.0 /24             地址池的地址范围

domain-name test.com      属于test.com域

default-router 1.1.1.1         PC的网关是多少

dns-server 1.1.1.1              DNS服务器是哪儿

exit

ip dhcp excluded-address 1.1.1.1 1.1.1.20    指定不分配出去的IP地址

 

以下是show run看到的

dhcp#show run
Building configuration...

Current configuration : 1013 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname dhcp
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
!
!
ip cef
ip dhcp excluded-address 1.1.1.1 1.1.1.20
!
ip dhcp pool test
   network 1.1.1.0 255.255.255.0
   default-router 1.1.1.1
   dns-server 1.1.1.1
   domain-name test.com
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex half
!        
interface FastEthernet1/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet1/1
 ip address 2.2.2.2 255.255.255.0
 duplex auto
 speed auto
!
router eigrp 1
 network 2.0.0.0
 no auto-summary
!
ip classless
no ip http server
!
!
!
!
!
!        
!
!
gatekeeper
 shutdown
!
!
line con 0
 transport preferred all
 transport output all
 stopbits 1
line aux 0
 transport preferred all
 transport output all
 stopbits 1
line vty 0 4
 login
 transport preferred all
 transport input all
 transport output all
!
!
end

 

 

验证结果

在PC上

pc#show ip inter f0/0
FastEthernet0/0 is up, line protocol is up
  Internet address is 1.1.1.21/24
  Broadcast address is 255.255.255.255
  Address determined by DHCP
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Local Proxy ARP is disabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is disabled
  IP fast switching on the same interface is disabled
  IP Flow switching is disabled
  IP CEF switching is disabled
  IP Null turbo vector
  IP Null turbo vector
  IP multicast fast switching is disabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are None
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Policy routing is disabled
  Network address translation is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled

实验完成，打完收功！！

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