查找IP地址对应端口的过程
在核心查找10.1.0.14对应的MAC 命令show arp | in 10.1.0.14
jushi-jiujiang-4506#show arp | in 10.1.0.14
Internet 10.1.0.14 1 00e0.6f06.5d80 ARPA Vlan1
Internet 10.1.0.143 1 0022.19cf.4a56 ARPA Vlan1
Internet 10.1.0.140 2 6c62.6dbe.699a ARPA Vlan1
Internet 10.1.0.145 31 0026.9e6f.05a6 ARPA Vlan1
Internet 10.1.0.144 1 00e0.4cea.7b4b ARPA Vlan1
Internet 10.1.0.149 1 6cf0.4981.efe9 ARPA Vlan1
在核心查出是从G2/5学到的sho mac address-table | in 00e0.6f06.5d80
jushi-jiujiang-4506#sho mac add
jushi-jiujiang-4506#sho mac address-table | in 00e0.6f06.5d80
1 00e0.6f06.5d80 dynamic ip,ipx,assigned,other GigabitEthernet2/5
查看G2/5接的是什么设备，首先看G2/5配置 sh run int g2/5，然后看G2/5的邻居信息sho cdp ne g2/5 de，发现是CheJian_3750G，地址为10.1.10.5
jushi-jiujiang-4506#sh run int g2/5
Building configuration...
Current configuration : 59 bytes
!
interface GigabitEthernet2/5
switchport mode trunk
end
jushi-jiujiang-4506#sho cdp ne g2/5 de
-------------------------
Device ID: CheJian_3750G
Entry address(es):
IP address: 10.1.10.5
Platform: cisco WS-C3750G-12S, Capabilities: Switch IGMP
Interface: GigabitEthernet2/5, Port ID (outgoing port): GigabitEthernet1/0/12
Holdtime : 132 sec
Version :
Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(25)SEE3, RELEASE SOFTWARE (fc2)
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Thu 22-Feb-07 15:04 by myl
advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000001CB1659380FF0000
VTP Management Domain: 'jushijiujiang'
Native VLAN: 1
Duplex: full
Management address(es):
IP address: 10.1.10.5
Unidirectional Mode: off
远程到10.1.10.5，查00e0.6f06.5d80是从哪个端口学到的sho mac address-table | in 00e0.6f06.5d80，发现是从Gi1/0/3学到的
jushi-jiujiang-4506#10.1.10.5
Trying 10.1.10.5 ... Open
User Access Verification
Password:
Password:
Password:
CheJian_3750G>en
Password:
CheJian_3750G#sho mac address-table | in 00e0.6f06.5d80
1 00e0.6f06.5d80 DYNAMIC Gi1/0/3
查看G1/0/3配置sh run int g1/0/3，为trunk，对端应该为交换机，查看G1/0/3邻居信息sho cdp ne g1/0/3 de，发现是从2918交换机223IDF-1-2学到的，地址为10.1.10.7
CheJian_3750G#sh run int g1/0/3
Building configuration...
Current configuration : 99 bytes
!
interface GigabitEthernet1/0/3
switchport trunk encapsulation dot1q
switchport mode trunk
end
CheJian_3750G#sho cdp ne g1/0/3 de
-------------------------
Device ID: 223IDF-1-2
Entry address(es):
IP address: 10.1.10.7
Platform: cisco WS-C2918-48TC-C, Capabilities: Switch IGMP
Interface: GigabitEthernet1/0/3, Port ID (outgoing port): GigabitEthernet0/1
Holdtime : 153 sec
Version :
Cisco IOS Software, C2918 Software (C2918-LANLITEK9-M), Version 12.2(44)SE6, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Mon 09-Mar-09 20:16 by gereddy
advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000002651441E80FF0000
VTP Management Domain: 'jushijiujiang'
Native VLAN: 1
Duplex: full
Management address(es):
IP address: 10.1.10.7
登陆到10.1.10.7，查看MAC是从哪个端口学到的sho mac address-table | in 00e0.6f06.5d80，
结果发现是从Fa0/7学到的，查看F0/7配置，此端口属于vlan 1
CheJian_3750G#10.1.10.7
Trying 10.1.10.7 ... Open
User Access Verification
Password:
223IDF-1-2>en
Password:
Password:
Password:
223IDF-1-2#sho mac address-table | in 00e0.6f06.5d80
1 00e0.6f06.5d80 DYNAMIC Fa0/7
223IDF-1-2#sh run int f0/7
Building configuration...
Current configuration : 33 bytes
!
interface FastEthernet0/7
end
223IDF-1-2#
223IDF-1-2#sho mac address-table interface f0/7
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
1 00e0.6f06.5d80 DYNAMIC Fa0/7
1 00e0.6f06.fe98 DYNAMIC Fa0/7
Total Mac Addresses for this criterion: 2
223IDF-1-2#
最后还发现F0/7下面还接了个HUB交换机（2个MAC判断出），然后再连至PC10.1.0.14，