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根据IP地址查交换机端口

在一个Cisco 交换网络中间,已知某台机器的IP地址,如何找出它连接到了哪台交换机的哪个端口上呢?最方便快捷的方法使使用CiscoWorks 2000 LMS网管软件的User tracking 功能,图形化界面,一目了然。

  如果没有这个软件,也可以使用以下手工分析方法来找出答案:

  示例网络:核心交换机为6509(交换引擎SE用CatOS, MSFC运行IOS软件)
  1. 找出该IP所对应的MAC地址:
  通过查看系统的ARP缓存表可以找出某IP所对应的MAC地址。由于ARP不能跨VLAN进行,所以连接各个VLAN的路由模块MSFC就是非常好的的选择--一般它在每一个VLAN都有一个端口(interface vlan n),能正确地进行ARP解释。
  6509MSFC#ping 10.10.1.65
  Type escape sequence to abort.
  Sending 5, 100-byte ICMP Echos to 10.10.1.65, timeout is 2 seconds:
  !!!!!
  Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
  6509MSFC#show arp | in 10.10.1.65
  Internet 10.10.1.65 2 0006.2973.121d ARPA Vlan2
  通过以上命令,我们知道10.10.1.65的MAC地址是0006.2973.121d, 这是IOS设备的MAC地址表达方式,在CatOS中,应写为00-06-29-73-12-1d.

  2.在交换机上找出MAC地址所对应的端口
  6509SE> (enable) show cam 00-06-29-73-12-1d
  * = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry.
  X = Port Security Entry $ = Dot1x Security Entry
  VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
         2 00-06-29-73-12-1d 9/41 [ALL]
  Total Matching CAM Entries Displayed =1

  这是不是说IP为 10.10.1.65的机器就接在端口9/41上呢?
  不一定。如果以下命令中显示该端口上只有一个活动的MAC地址,那么答案就是肯定的:
  6509SE> (enable) show cam dynamic 9/41
  * = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry.
  X = Port Security Entry $ = Dot1x Security Entry
  VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
  ---- ------------------ ----- -------------------------------------------

  2 00-06-29-73-12-1d 9/41 [ALL]
  Total Matching CAM Entries Displayed =1
  如果该命令显示该端口上有多个活动的MAC地址,那么这个端口应该连接到别的交换机或HUB设备上,见下面的例子(查找IP为10.10.1.250所对应的交换机端口):

  6509MSFC#ping 10.10.1.250
  Type escape sequence to abort.
  Sending 5, 100-byte ICMP Echos to 10.10.1.250, timeout is 2 seconds:
  !!!!!
  Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
  6509MSFC#show arp | in 10.10.1.250
  Internet 10.10.1.250 4 0009.6b8c.64ec ARPA Vlan2
  6509SE> (enable) show cam 00-09-6b-8c-64-ec
  * = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry.
  X = Port Security Entry $ = Dot1x Security Entry
  VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
  ---- ------------------ ----- -------------------------------------------

  2 00-09-6b-8c-64-ec 3/11 [ALL]
  Total Matching CAM Entries Displayed =1
  6509SE> (enable) show cam dy 3/11
  * = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry.
  X = Port Security Entry $ = Dot1x Security Entry
  VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
         1 00-03-e3-4b-06-80 3/11 [ALL]
  1 00-08-02-e6-b0-cd 3/11 [ALL]
  1 00-02-a5-ee-f2-4f 3/11 [ALL]
  1 00-09-6b-8c-66-d6 3/11 [ALL]
  1 00-09-6b-63-17-d9 3/11 [ALL]
  1 00-0b-cd-03-ec-f5 3/11 [ALL]
  1 00-09-6b-63-17-d8 3/11 [ALL]
  1 00-08-02-e6-b0-c1 3/11 [ALL]
  1 00-08-02-e6-b0-85 3/11 [ALL]
  1 00-08-02-e6-b0-81 3/11 [ALL]
  1 00-02-a5-ef-16-af 3/11 [ALL]
  1 00-02-a5-ee-f2-93 3/11 [ALL]
  1 00-02-55-c6-05-61 3/11 [ALL]
  2 00-09-6b-8c-64-ec 3/11 [ALL]
  1 00-08-02-e6-b0-ed 3/11 [ALL]
  1 00-08-02-e6-b0-a9 3/11 [ALL]
  1 00-02-55-54-7a-e0 3/11 [ALL]
  1 00-02-a5-ef-15-a6 3/11 [ALL]
  1 00-08-02-e6-af-8f 3/11 [ALL]
  1 00-08-02-e6-b0-bd 3/11 [ALL]
  1 00-0b-cd-03-db-8b 3/11 [ALL]
  1 00-09-6b-8c-25-50 3/11 [ALL]
  Do you wish to continue y/n [n]? n

  由于该端口连接到另一台交换机或HUB,必须继续追查,方法如下:
  6509SE> (enable) show cdp nei 3/11
  * - indicates vlan mismatch.
  # - indicates duplex mismatch.
  Port Device-ID Port-ID Platform
  -------- ------------------------------- ------------------------- ------------

  3/11 Cisco2924 GigabitEthernet1/1 cisco WS-C2924M-XL
  该命令显示对端设备是一台Cisco2924,如果没有显示,那么说明连接的是别的厂家的设备,可能要到该交换机上用类似的办法继续追查。本例子中是Cisco 设备,所有我们可以继续:

  6509SE> (enable) show cdp nei 3/11 de
  Port (Our Port): 3/11
  Device-ID: Cisco2924
  Device Addresses:
  IP Address: 10.10.0.60
  Holdtime: 153 sec
  Capabilities: TRANSPARENT_BRIDGE SWITCH
  Version:
  Cisco Internetwork Operating System Software
  IOS (tm) C2900XL Software (C2900XL-C3H2S-M), Version 12.0(5.2)XU, MAINTENANCE INTERIM SOFTWARE
  Copyright (c) 1986-2000 by cisco Systems, Inc.
        Compiled Mon 17-Jul-00 17:35 by ayounes
  Platform: cisco WS-C2924M-XL
  Port-ID (Port on Neighbors''s Device): GigabitEthernet1/1
  VTP Management Domain: lan
  Native VLAN: 1
  Duplex: full
  System Name: unknown
  System Object ID: unknown
  Management Addresses: unknown
  Physical Location: unknown
  Cisco2924#show mac-address-table dynamic address 0009.6b8c.64ec
  Non-static Address Table:
  Destination Address Address Type VLAN Destination Port
  ------------------- ------------ ---- --------------------
  0009.6b8c.64ec Dynamic 2 FastEthernet0/2
  Cisco2924#show mac-address-table dynamic interface f0/2
  Non-static Address Table:
  Destination Address Address Type VLAN Destination Port
  ------------------- ------------ ---- --------------------
  0009.6b8c.64ec Dynamic 2 FastEthernet0/2
  通过以上命令可知,MAC地址0009.6b8c.64ec 与Cisco 2924交换机相连,且是该端口上唯一活动的MAC地址,所以IP为10.10.1.250的机器应该就连接在这个端口上。

 

转载地址:http://www.netsp.com.cn/Article/config/cisco/switch/200512/20051222111847.html

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