根據IP查連接埠

在一個Cisco 交換網路中間，已知某台機器的IP地址，如何找出它串連到了哪台交換器的哪個連接埠上呢？最方便快捷的方法使使用CiscoWorks 2000 LMS網管軟體的User tracking 功能，圖形化介面，一目瞭然。

如果沒有這個軟體，也可以使用以下手工分析方法來找出答案：

樣本網路：核心交換器為6509(交換引擎SE用CatOS, MSFC運行IOS軟體)

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1. 找出該IP所對應的MAC地址:

通過查看系統的ARP緩衝表可以找出某IP所對應的MAC地址。由於ARP不能跨VLAN進行，所以串連各個VLAN的路由模組MSFC就是最佳的選擇－－一般它在每一個VLAN都有一個連接埠(interface vlan n)，能正確地進行ARP解釋。

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

通過以上命令，我們知道10.10.1.65的MAC地址是0006.2973.121d, 這是IOS裝置的MAC地址表達方式，在CatOS中，應寫為00-06-29-73-12-1d.

2.在交換器上找出MAC地址所對應的連接埠

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

這是不是說IP為 10.10.1.65的機器就接在連接埠9/41上呢？

不一定。如果以下命令中顯示該連接埠上只有一個活動的MAC地址，那麼答案就是肯定的：

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

如果該命令顯示該連接埠上有多個活動的MAC地址，那麼這個連接埠應該串連到別的交換器或HUB裝置上，見下面的例子（尋找IP為10.10.1.250所對應的交換器連接埠）:

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]

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