Duplicate IP address on Vlan

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Overall Rating: 4 (2 ratings)
ericgarnel Thu, 02/19/2009 - 07:03

It sounds like you have a duplicate address

having said that, here is a way to find it.

on the 4500

SXSW_4506>sh mac address-table | include 17dc

230 0013.7256.17dc dynamic ip FastEthernet3/1

You would replace "17dc" with "4858" and then again with "47ed"

examine the output, if the interface is a trunk to another switch, run the same commands on that switch. repeat the process until the output indicates a port local to that switch and you will find your culprit

having cdp enabled will help you on your quest

arumugam006 Wed, 03/25/2009 - 16:39


When i execute the command,

6509-E>sh mac-address-table | in 5c00

* --- 0014.f1fb.5c00 static No - Router

* --- 0014.f1fb.5c00 static No - Router

* --- 0014.f1fb.5c00 static No - Router

* --- 0014.f1fb.5c00 static No - Router

How do we troubleshoot further on this case.

Leo Laohoo Wed, 03/25/2009 - 16:44

Hi Arumugam,

The MAC address is a Cisco appliance. What are the error messages you are getting?

Leo Laohoo Thu, 02/19/2009 - 14:41

Two machines have the same IP Address. Could be caused by both of them are statically configured or one is.

Eric's post will help you find out where they are coming from. Judging from the error messages that they are coming from the same VLAN (VLAN 601), chances are they might be coming from one switch.

When you do find one, change the IP Address and this should fix your problem.

Hope this helps.

Leo Laohoo Thu, 02/19/2009 - 16:28

Thanks for the rating.

Also, if I may be allowed to add, I was looking at your error message. The two MAC addresses are similar, except for the last bit.

Is someone imaging Dell machines?

Leo Laohoo Thu, 02/19/2009 - 21:55

Thanks for the ratings. Let us know if you need further assistance.

WEERAKOO69BA Sun, 06/24/2012 - 00:52


I am facing the similar kind of problem.I am getting the following eror

2w4d: %IP-4-DUPADDR: Duplicate address on Vlan113, sourced by 001f.6c88.4dff

so I shut and noshut vlan 113,

now I am geting ,

2w4d: %IP-4-DUPADDR: Duplicate address on Vlan196, sourced by 001f.6c88.4fff

Can anybody help me?


Leo Laohoo Sun, 06/24/2012 - 01:30

The MAC address "001f.6c88.4fff" belongs to a Cisco appliance.

Shut down either one of the two VLANs (113 or 196) and track down where the appliance is and change the IP address accordingly.


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