三层交换与DHCP中继

实验拓朴:

 

 

 

 

 

实验目标:

 

 

目标1.配置三层交换，是内部VLAN间互通

 

目标2.配置DHCP中继，使VLAN2中的DHCP SERVER对VLAN3中的CLIENT生效

 

 

 

 

实验拓朴改动说明:

 

Switch1 F0/0 <----> Router1 E0/0
Switch1 F0/15 <----> Switch2 F0/15
Switch2 F0/2 <----> XPC P0/1          (net1 vlan2 ，VS4 ，做DHCP SERVER)
Switch2 F0/3 <----> XPC P0/0          (net8　 vlan3 ，VS3  CLIENT)

 

在二层交换机上我只桥接了2台虚拟PC，VS4 ，VS3
VS4 ：IP：192.168.2.1  /24
             GW：192.168.2.54     VLAN 2
VS3：IP：192.168.3.1   / 24
             GW：192.168.3.254      VLAN3

VLAN 1 不用。  

 

实验步骤:   

 

目标1:配置三层交换是内部VLAN之间可以互通.

 

1． sw1-3(config)#in                ( trunk start)
sw1-3(config)#interface f0/15
sw1-3(config-if)#sw
sw1-3(config-if)#switchport mo
sw1-3(config-if)#switchport mode tr
sw1-3(config-if)#no sh
sw1-3(config)#interface f0/0
sw1-3(config-if)#sw
sw1-3(config-if)#switchport mo
sw1-3(config-if)#switchport mode tr
sw1-3(config-if)#switchport mode trunk
sw1-3(config-if)#no sh

 

2.  sw1-3#vl da                          (config vtp server)
sw1-3(vlan)#vtp domain test
Changing VTP domain name from NULL to test
sw1-3(vlan)#vtp server
Device mode already VTP SERVER.
sw1-3(vlan)#vtp password 111111
Setting device VLAN database password to 111111.
sw1-3(vlan)#vtp v2-mode
V2 mode enabled.
sw1-3(vlan)#vtp pruning
Pruning switched ON
sw1-3(vlan)#exit

 

3.  sw2-2
 start  trunk                       (和SW1-3 相同配置，略)
 config vtp client             （和SW1-3配置差不多，略）

 

4． sw1-3#vl da
sw1-3(vlan)#vlan 2 name v2
VLAN 2 added:
    Name: v2
sw1-3(vlan)#apply
APPLY completed.
sw1-3(vlan)#vlan 3 name v3
VLAN 3 added:
    Name: v3
sw1-3(vlan)#apply
APPLY completed.
sw1-3(vlan)#exit
APPLY completed.
Exiting....
sw1-3#exit

 

5． CLIENT TEST

 

sw2-2#show vlan-switch

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/0, Fa0/1, Fa0/2, Fa0/3
                                                Fa0/4, Fa0/5, Fa0/6, Fa0/7
                                                Fa0/8, Fa0/9, Fa0/10, Fa0/11
                                                Fa0/12, Fa0/13, Fa0/14
2    v2                               active   
3    v3                               active   
1002 fddi-default                     active   
1003 trcrf-default                    active   
1004 fddinet-default                  active   
1005 trbrf-default                    active   

 

6． sw2-2#conf t                                                （划分接口到VLAN中）
Enter configuration commands, one per line.  End with CNTL/Z.
sw2-2(config)#interface f0/2
sw2-2(config-if)#switchport access vlan 2
sw2-2(config-if)#switchport mode access        （定义为二层接口）
sw2-2(config-if)#no sh
sw2-2(config-if)#exit
sw2-2(config)#interface f0/3
sw2-2(config-if)#switchport access vlan 3
sw2-2(config-if)#switchport mode access
sw2-2(config-if)#no sh
sw2-2(config-if)#exit
sw2-2(config)#exit
sw2-2#

 

 

7．sw2-2#show vlan-switch         ( test)

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/0, Fa0/1, Fa0/4, Fa0/5
                                                Fa0/6, Fa0/7, Fa0/8, Fa0/9
                                                Fa0/10, Fa0/11, Fa0/12, Fa0/13
                                                Fa0/14
2    v2                               active    Fa0/2
3    v3                               active    Fa0/3
1002 fddi-default                     active   
1003 trcrf-default                    active   
1004 fddinet-default                  active   
1005 trbrf-default                    active   

 

8.  sw1-3(config)#ip routing          (start 路由功能)

 

9． sw1-3(config)#interface vlan 2       （三层交换机上VLAN 配IP。为二层VLAN GW）
sw1-3(config-if)#ip add 192.168.2.254 255.255.255.0
sw1-3(config-if)#no sh
sw1-3(config-if)#exit
sw1-3(config)#interface vlan 3
sw1-3(config-if)#ip add 192.168.3.254 255.255.255.0
sw1-3(config-if)#no sh
sw1-3(config-if)#exit

sw1-3#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set
C    192.168.2.0/24 is directly connected, Vlan2
C    192.168.3.0/24 is directly connected, Vlan3

 

10．sw1-3#show ip in br        （ TEST）
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            unassigned      YES unset  up                    up     
FastEthernet0/1            unassigned      YES unset  up                    down   
FastEthernet0/2            unassigned      YES unset  up                    down   
FastEthernet0/3            unassigned      YES unset  up                    down   
FastEthernet0/4            unassigned      YES unset  up                    down   
FastEthernet0/5            unassigned      YES unset  up                    down   
FastEthernet0/6            unassigned      YES unset  up                    down   
FastEthernet0/7            unassigned      YES unset  up                    down   
FastEthernet0/8            unassigned      YES unset  up                    down   
FastEthernet0/9            unassigned      YES unset  up                    down   
FastEthernet0/10           unassigned      YES unset  up                    down   
FastEthernet0/11           unassigned      YES unset  up                    down   
FastEthernet0/12           unassigned      YES unset  up                    down   
FastEthernet0/13           unassigned      YES unset  up                    down   
FastEthernet0/14           unassigned      YES unset  up                    down   
FastEthernet0/15           unassigned      YES unset  up                    up     
Vlan1                      unassigned      YES unset  up                    up     
Vlan2                      192.168.2.254   YES manual up                    up     
Vlan3                      192.168.3.254   YES manual up                    up     

 

11.测试不同的VLAN间是否能正常通信.

 

1> V2 -----VS4.

 

 

2> V3-----VS3

 

 

 

 

 

 

12． 在三层交换机上配置路由接口和IP ，并运行RIP 。在路由器上配置相应接口的IP ，并运行RIP，结果，使VALN 2 和VLAN 3 中的主机可以通过三层交换和外部相通。

 

sw1-3(config-if)#interface f0/0                 
sw1-3(config-if)#no switchport               （ 关掉接口交换功能）
sw1-3(config-if)#ip add 192.168.5.1 255.255.255.0
sw1-3(config-if)#no sh
sw1-3(config-if)#exit
sw1-3(config)#exit

 

sw1-3#show ip in br
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.5.1     YES manual up                    up     
FastEthernet0/1            unassigned      YES unset  up                    down

sw1-3(config)#router rip                   （运行RIP）
sw1-3(config-router)#network 192.168.5.0
sw1-3(config-router)#network 192.168.2.0
sw1-3(config-router)#network 192.168.3.0
sw1-3(config-router)#exit
sw1-3(config)#exit

sw1-3#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C    192.168.5.0/24 is directly connected, FastEthernet0/0
R    192.168.6.0/24 [120/1] via 192.168.5.2, 00:00:03, FastEthernet0/0
C    192.168.2.0/24 is directly connected, Vlan2
C    192.168.3.0/24 is directly connected, Vlan3

sw1-3#

R1(config)#interface e0/0
R1(config-if)#ip add 192.168.5.2 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exi
R1(config)#interface lo0                            （环回）
R1(config-if)#ip add 192.168.6.1 255.255.255.0      
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#exit

 

R1#show ip in br
Interface                  IP-Address      OK? Method Status                Protocol
Ethernet0/0                192.168.5.2     YES manual up                    up     
Ethernet0/1                unassigned      YES unset  administratively down down   
Ethernet0/2                unassigned      YES unset  administratively down down   
Ethernet0/3                unassigned      YES unset  administratively down down   
Loopback0                  192.168.6.1     YES manual up                    up 

 

R1(config)#router rip                      （运行RIP）
R1(config-router)#network 192.168.5.0
R1(config-router)#network 192.168.6.0
R1(config-router)#exit
R1(config)#exit

 

R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C    192.168.5.0/24 is directly connected, Ethernet0/0
C    192.168.6.0/24 is directly connected, Loopback0
R    192.168.2.0/24 [120/1] via 192.168.5.1, 00:00:03, Ethernet0/0
R    192.168.3.0/24 [120/1] via 192.168.5.1, 00:00:03, Ethernet0/0

 

13.测试前面的配置结果.

 

14.测试成功后,下一步,反之,检查是那个地方配错.

 

目标2:配置DHCP中继，使VLAN2中的DHCP SERVER对VLAN3中的CLIENT生效.

 

1.在VLAN2中的主机中配置DHCP SERVER.使它能为VLAN3中的CLINET动态分配IP地址.

 

2.在本地的客户端测试能否行到IP地址.

 

 

成功.

 

3.要VLAN3上的客户机上进行测试,看是否能得到IP地址.

 

 

失败了.

 

原因很明:  之所以VLAN 3中的CLIENT 没有得到IP ，是因为不同VLAN 之间相通是要通过路由的，而在，申请IP时，用的是广播地址，路由是隔离广播的，所以，没有得以IP ，

 

4.解决的方法:就是在，三层交换机 上面做中继代理.

 

sw1-3(config)#interface vlan 2
sw1-3(config-if)#ip helper-address 192.168.2.1
sw1-3(config-if)#exit

sw1-3(config)#interface vlan 3
sw1-3(config-if)#ip helper-address 192.168.2.1
sw1-3(config-if)#exit
sw1-3(confi)

 

5.配置完中继代理测试.

 

 

配置成功.

 

 

 

 

 

 

 

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