2020-02-23

大学回顾复习-网络知识 

HSRP-思科专有的热备份路由协议 (过一段时间不看不敲命令,还真的会忘记)

做个试验,动手敲命令,抓包看看试验

比如。。。内网DMZ区域有一台服务器,是某个公司的对我官方网站所在的服务器,外边有位客户想访问该公司的官方服务器(内网里的其他设施均已隐藏,这样看起来更直观)

先配置IP地址,再采用默认路由,静态路由,或者路由协议 RIP或者OSPF让网络互通

最后再弄HSRP,我这边直接弄RIP,再HSRP

刚刚搭建起来什么命令都没有敲,但是始终有一个个起不来,那是因为交换机默认的STP协议起了作用,阻塞一个端口防止环路生成

先配置好IP地址

Switch>enable

Switch#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)#interface FastEthernet0/2

Switch(config-if)#no switchport

Switch(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

Switch(config-if)#

Switch(config-if)#ip address 192.168.2.1 255.255.255.0

Switch(config-if)#no shutdown

Switch(config-if)#end

Switch#

%SYS-5-CONFIG_I: Configured from console by console


Switch#write

Building configuration...

[OK]

Switch#

Switch#

Switch#

Switch#

Switch#CONF T

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)#hostname sw1

sw1(config)#

Switch#

Switch#CONF T

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)#hostname sw1

sw1(config)#

sw1(config)#

sw1(config)#

sw1(config)#interface FastEthernet0/2

sw1(config-if)#

sw1(config-if)#exit

sw1(config)#interface FastEthernet0/1

sw1(config-if)#no sw

sw1(config-if)#no switchport

sw1(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

sw1(config-if)#ip add 192.168.1.252 255.255.255.0

sw1(config-if)#no shutdown

sw1(config-if)#

接着是switch2

Switch(config)#hostname sw2

sw2(config)#

sw2(config)#interface FastEthernet0/1

sw2(config-if)#

sw2(config-if)#exit

sw2(config)#interface FastEthernet0/1

sw2(config-if)#no switchport

sw2(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

sw2(config-if)#

sw2(config-if)#ip add 192.168.1.253 255.255.255.0

sw2(config-if)#no shutdown

sw2(config-if)#

sw2(config-if)#exit

sw2(config)#interface FastEthernet0/1

sw2(config-if)#exit

sw2(config)#interface fa

sw2(config)#interface fastEthernet 0/2

sw2(config-if)#no sw

sw2(config-if)#no switchport

sw2(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

sw2(config-if)#ip add 192.168.3.1 255.255.255.0

sw2(config-if)#no shutd

sw2(config-if)#no shutdown

sw2(config-if)#end

sw2#

%SYS-5-CONFIG_I: Configured from console by console

write

Building configuration...

[OK]

sw2#

接下来是sw3

Switch>enable

Switch#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)#interface FastEthernet0/1

Switch(config-if)#ex

Switch(config)#hostname sw3

sw3(config)#

sw3(config)#interface FastEthernet0/1

sw3(config-if)#

sw3(config-if)#exit

sw3(config)#interface FastEthernet0/1

sw3(config-if)#no sw

sw3(config-if)#no switchport

sw3(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

sw3(config-if)#ip add 192.168.2.2 255.255.255.0

sw3(config-if)#no shut

sw3(config-if)#no shutdown

sw3(config-if)#

sw3(config-if)#exit

sw3(config)#interface FastEthernet0/1

sw3(config-if)#

sw3(config-if)#exit

sw3(config)#interface FastEthernet0/2

sw3(config-if)#no sw

sw3(config-if)#no switchport

sw3(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

sw3(config-if)#

sw3(config-if)#ip add 192.168.3.2 255.255.255.0

sw3(config-if)#no shut

sw3(config-if)#no shutdown

sw3(config-if)#ex

sw3(config)#inter

sw3(config)#interface fa

sw3(config)#interface fastEthernet 0/3

sw3(config-if)#no sw

sw3(config-if)#no switchport

sw3(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up

sw3(config-if)#

sw3(config-if)#ip add 192.168.4.254 255.255.255.0

sw3(config-if)#no sh

sw3(config-if)#no shutdown

sw3(config-if)#end

sw3#

%SYS-5-CONFIG_I: Configured from console by console

sw3#

sw3#write

Building configuration...

[OK]

sw3#

接着是配置路由协议

sw1(config)#router rip

sw1(config-router)#vers

sw1(config-router)#version 2

sw1(config-router)#no auto-sumarry

                              ^

% Invalid input detected at '^' marker.

sw1(config-router)#no auto-summary

sw1(config-router)#network 192.168.1.0

sw1(config-router)#network

sw1(config-router)#network 192.168.2.0

sw1(config-router)#

sw1(config-router)#end

sw1#

%SYS-5-CONFIG_I: Configured from console by console

sw1#

sw1#write

Building configuration...

[OK]

sw1#

sw2>

sw2>enable

sw2#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

sw2(config)#

sw2(config)#

sw2(config)#router

sw2(config)#router rip

IP routing not enabled

sw2(config)#ip routing

sw2(config)#router rip

sw2(config-router)#version 2

sw2(config-router)#no auto-summary

sw2(config-router)#network 192.168.1.0

sw2(config-router)#net

sw2(config-router)#network 192.168.3.0

sw2(config-router)#end

sw2#

%SYS-5-CONFIG_I: Configured from console by console

sw2#write

Building configuration...

[OK]

sw2#

sw3>

sw3>

sw3>enable

sw3#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

sw3(config)#ip routing

sw3(config)#router rip

sw3(config-router)#version 2

sw3(config-router)#no auto-summary

sw3(config-router)#neot

sw3(config-router)#network 192.168.2.0

sw3(config-router)#network 192.168.3.0

sw3(config-router)#network 192.168.4.0

sw3(config-router)#end

sw3#

%SYS-5-CONFIG_I: Configured from console by console

sw3#

sw3#write

Building configuration...

[OK]

sw3#

接着在三层设备上show ip router

sw3#show ip route

sw3#show ip route

Codes: C - connected, S - static, I - IGRP, 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, E - EGP

      i - IS-IS, 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

R    192.168.1.0/24 [120/1] via 192.168.3.1, 00:00:02, FastEthernet0/2

                    [120/1] via 192.168.2.1, 00:00:09, FastEthernet0/1

C    192.168.2.0/24 is directly connected, FastEthernet0/1

C    192.168.3.0/24 is directly connected, FastEthernet0/2

C    192.168.4.0/24 is directly connected, FastEthernet0/3

sw3#

sw1#show ip route

Codes: C - connected, S - static, I - IGRP, 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, E - EGP

      i - IS-IS, 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    192.168.1.0/24 is directly connected, FastEthernet0/1

C    192.168.2.0/24 is directly connected, FastEthernet0/2

R    192.168.3.0/24 [120/1] via 192.168.1.253, 00:00:18, FastEthernet0/1

                    [120/1] via 192.168.2.2, 00:00:06, FastEthernet0/2

R    192.168.4.0/24 [120/1] via 192.168.2.2, 00:00:06, FastEthernet0/2

sw2>

sw2>

sw2>enable

sw2#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

sw2(config)#

sw2(config)#

sw2(config)#router

sw2(config)#router rip

IP routing not enabled

sw2(config)#ip routing

sw2(config)#router rip

sw2(config-router)#version 2

sw2(config-router)#no auto-summary

sw2(config-router)#network 192.168.1.0

sw2(config-router)#net

sw2(config-router)#network 192.168.3.0

sw2(config-router)#end

sw2#

%SYS-5-CONFIG_I: Configured from console by console

sw2#write

Building configuration...

[OK]

sw2#

sw2#

sw2#show ip route

Codes: C - connected, S - static, I - IGRP, 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, E - EGP

      i - IS-IS, 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    192.168.1.0/24 is directly connected, FastEthernet0/1

R    192.168.2.0/24 [120/1] via 192.168.1.252, 00:00:15, FastEthernet0/1

                    [120/1] via 192.168.3.2, 00:00:23, FastEthernet0/2

C    192.168.3.0/24 is directly connected, FastEthernet0/2

R    192.168.4.0/24 [120/1] via 192.168.3.2, 00:00:23, FastEthernet0/2

sw2#

C是直连路由 ,R是rip路由,O是ospf路由

接着测试网络是否互通



可以看到网络通了

接着配置HSRP

sw1(config)#interface FastEthernet0/1

sw1(config-if)#standby 1 ip 192.168.1.254

sw1(config-if)#standby 1 priority 200

sw1(config-if)#

%HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Speak -> Standby

%HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Standby -> Active

sw2>enable

sw2#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

sw2(config)#interface FastEthernet0/1

sw2(config-if)#standby 1 ip 192.168.1.254

sw2(config-if)#standby 1 prio

sw2(config-if)#standby 1 priority

%HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 stat

sw2(config-if)#standby 1 priority 195

sw2(config-if)#

分别在SW1和SW2上查看HSRP信息

sw1(config-if)#

sw1(config-if)#END

sw1#

%SYS-5-CONFIG_I: Configured from console by console

sw1#

sw1#show standby brief

                    P indicates configured to preempt.

                    |

Interface  Grp  Pri P State    Active          Standby        Virtual IP

Fa0/1      1    200  Active  local          192.168.1.253  192.168.1.254 

sw1#

sw2(config-if)#exit

sw2(config)#do show standby brief

                    P indicates configured to preempt.

                    |

Interface  Grp  Pri P State    Active          Standby        Virtual IP

Fa0/1      1    195  Standby  192.168.1.252  local          192.168.1.254 

sw2(config)#

我们可以看到,一个虚拟路由器已经形成,虚拟IP 192.168.1.254  HSRP热备份组中的活动路由器是192.168.1.252 也就是SW1

接着,我们尝试访问webserver(192.168.1.1/24),看看是否起作用了,这里的web-server的网关就是192.168.1.254


我们可以看到已经互通了

接着我们来抓包(用192.168.4.1来ping一下web-server192.168.1.1这台服务器),看看数据是不是从sw1流过 (可以使用思科自带的,或者使用wireshark)



可以看到数据包流量确实是从sw1经过。





等到包到达server后,server再转发到二层交换机,看看二层交换机是怎么样转发的


我们可以看到,这个二层交换机视乎把SW1和SW2都当成了server的网关设备,即SW1和SW2组成的热备份虚拟路由器,而且,因为sw2是备份路由器,所以SW2默认会把包丢弃掉,只会让SW1这个活动路由器转发这个ICMP数据包

我们近距离来看看这个数据包的内容



源物理地址和IP地址都是对的上的

接着SW1转发给SW3,确实是只有SW1这一条路


当ICMP数据包到达PC0后,我们可以看到,对应的第三个ICMP回应包收到了


接着,我们来模拟活动路由器down掉的情况,看看备份路由器是不是会主动转变成为活动路由器


我们可以看到,数量流量是从SW2经过的,但是,SW2任然是备份,这是因为SW2没有配置占先权,而且SW1也没完全down,只是上游端口不通,但是SW1的优先级已经从200降到190了


所以,我们在SW2的fa0/1配置占先权,把SW1的fa0/2端口开起来,重新模拟(不把端口开起来,就算配置了占先权也没用,因为只有活跃路由器down掉才会重新选举)






我们可以看到活跃路由器已经成为备份路由器,而备份路由器已经变成活跃路由器


取消SW2接口的占先权,把SW1接口配置占先权,并且把fa0/2接口开启,可以看到又重新变回原来的样子了


接下来,我们两个SW都配置了占先权,我们来看看,再次模拟SW1的fa0/2接口down掉,看看活动路由器的选举是谁





我们可以看到SW2再次变为活动路由器了,而且SW1的priority从195再次减少变成190了,而SW2的优先级不变,还是195


总结:  standby 1 preempt 占先权必须要配置,不然即使活跃路由器down掉,备份路由器也不会主动变成活跃路由器,都配置占先权的情况下,优先级高的成为活跃路由器







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