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VLAN-----与外网互通的三层交换

程序员文章站 2022-06-13 12:37:36
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一.实验环境

  • GNS3模拟器（CRT终端，wireshark抓包工具）
  • 三台VPCs
  • 三台c3725路由器（两台改成交换机）

二.实验原理和目的

工作原理：数据从PC1发出经由二层交换标记vlan10并转发， 从中继链路发往三层交换机上，三层交换机拆分信息识别目的IP地址之后寻找 相应的虚拟子接口，再把信息重新封装、标记，发往二层交换机上，二层设备识别标签并且脱掉标签，把信息发给PC2.

目的：使得pc1，pc2这两个不同网段不同vlan能通信，使得pc1，pc2能够访问外网pc3，但是pc3不能访问pc1，pc2（注：这里应使用ACL和NAT，使外网不能访问内网，但是笔者并未学习，所以仅在R1上配置静态路由，使pc1，pc2，pc3互通）

三.网络拓扑图

VLAN-----与外网互通的三层交换

四.实验步骤

  • 配置pc1，pc2，pc3的IP地址和默认网关

PC1> ip 192.168.10.10 255.255.255.0 192.168.10.1
Checking for duplicate address...
PC1 : 192.168.10.10 255.255.255.0 gateway 192.168.10.1
PC2> ip 192.168.20.20 255.255.255.0 192.168.20.1
Checking for duplicate address...
PC1 : 192.168.20.20 255.255.255.0 gateway 192.168.20.1
PC3> ip 20.0.0.2 255.255.255.0 20.0.0.1
Checking for duplicate address...
PC1 : 20.0.0.2 255.255.255.0 gateway 20.0.0.1

  • 配置sw-2

  • 分别划分vlan10，20给端口f1/0，f1/1，并且验证vlan
sw-2(config)#vlan 10,20
sw-2(config-vlan)#int f1/0
sw-2(config-if)#sw mo acc
sw-2(config-if)#sw acc vlan 10
sw-2(config-if)#int f1/1
sw-2(config-if)#sw mo acc
sw-2(config-if)#sw acc vlan 20
sw-2(config)#do show vlan-sw b

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa1/3, Fa1/4, Fa1/5, Fa1/6
                                                Fa1/7, Fa1/8, Fa1/9, Fa1/10
                                                Fa1/11, Fa1/12, Fa1/13, Fa1/14
                                                Fa1/15
10   VLAN0010                         active    Fa1/0
20   VLAN0020                         active    Fa1/1
1002 fddi-default                     act/unsup 
1003 token-ring-default               act/unsup 
1004 fddinet-default                  act/unsup 
1005 trnet-default                    act/unsup
  • 给f1/2端口设置trunk，并且验证f1/2端口
sw-2(config-if)#int f1/2
sw-2(config-if)#sw mo tr
sw-2(config-if)#sw tr en do
sw-2(config-if)#do show int f1/2 switchport
Name: Fa1/2
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1,10,20
Protected: false
Priority for untagged frames: 0
Override vlan tag priority: FALSE
Voice VLAN: none 
Appliance trust: none

  • 配置sw-3

  • 给f1/1给配置vlan10，20，并给f1/1配置trunk,且验证f1/1的信息
sw-3#conf t
sw-3(config)#vlan 10,20
sw-3(config-vlan)#int f1/1
sw-3(config-if)#sw mo trunk
sw-3(config-if)#sw tr en do
sw-3(config-if)#do show int f1/1 switchport
Name: Fa1/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1,10,20
Protected: false
Priority for untagged frames: 0
Override vlan tag priority: FALSE
Voice VLAN: none 
Appliance trust: none
  • 给sw-3虚拟接口配置IP地址和子网掩码,并查看路由表
sw-3(config)#int vlan 10
sw-3(config-if)#ip add  192.168.10.1 255.255.255.0
sw-3(config-if)#no shut
sw-3(config)#int vlan 20
sw-3(config-if)#ip add  192.168.20.1 255.255.255.0
sw-3(config-if)#no shut
sw-3(config-if)#do 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    192.168.10.0/24 is directly connected, Vlan10
C    192.168.20.0/24 is directly connected, Vlan20

 

  • 先关闭f1/2的二层功能，再给f1/2接口配置IP地址和静态路由，使数据包能够到达pc3，并验证信息
sw-3(config)#int f1/2
sw-3(config-if)#no switch
sw-3(config-if)#ip add 10.0.0.1 255.255.255.0
sw-3(config-if)#no shut
sw-3(config-if)#exit      
sw-3(config)#ip route 20.0.0.0 255.255.255.0 10.0.0.2
sw-3(config)#do 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

     20.0.0.0/24 is subnetted, 1 subnets
S       20.0.0.0 [1/0] via 10.0.0.2
C    192.168.10.0/24 is directly connected, Vlan10
C    192.168.20.0/24 is directly connected, Vlan20
     10.0.0.0/24 is subnetted, 1 subnets
C       10.0.0.0 is directly connected, FastEthernet1/2

  • 配置R1

  • 配置R1接口的IP地址和再f0/0接口上通向pc1，pc2的静态路由，并验证信息
R1#conf t
R1(config)#int f0/0
R1(config-if)#ip add 10.0.0.2 255.255.255.0
R1(config-if)#no shut
R1(config-if)#int f0/1 
R1(config-if)#ip add 20.0.0.1 255.255.255.0                     
R1(config-if)#no shut
R1(config)#int f0/1
R1(config-if)#ip route 192.168.10.0 255.255.255.0 10.0.0.1
R1(config)#int f0/1                                    
R1(config-if)#ip route 192.168.20.0 255.255.255.0 10.0.0.1
R1(config)#do 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

     20.0.0.0/24 is subnetted, 1 subnets
C       20.0.0.0 is directly connected, FastEthernet0/1
S    192.168.10.0/24 [1/0] via 10.0.0.1
S    192.168.20.0/24 [1/0] via 10.0.0.1
     10.0.0.0/24 is subnetted, 1 subnets
C       10.0.0.0 is directly connected, FastEthernet0/0

 

 

五.实验结果

  • PC1，PC2，PC3之间的互ping

VLAN-----与外网互通的三层交换

 

VLAN-----与外网互通的三层交换

 

VLAN-----与外网互通的三层交换

 

  • 使用抓包工具在sw-2和sw-3之间查看信息流

VLAN-----与外网互通的三层交换

 

VLAN-----与外网互通的三层交换

VLAN-----与外网互通的三层交换

 

实验结束！

相关标签： 三层交换

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