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Duplicate IP address on Vlan

edmond.chiu
Level 1
Level 1

I am getting the following error messge on Cat4500:

Feb 18 23:37:53.098: %IP-4-DUPADDR: Duplicate address 10.237.66.3 on Vlan601, sourced by 001d.096b.4858

Feb 18 23:38:58.092: %IP-4-DUPADDR: Duplicate address 10.237.66.3 on Vlan601, sourced by 001d.096b.47ed

What could be wrong? Appreciate any assistance.

10 Replies 10

ericgarnel
Level 7
Level 7

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

Hi,

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.

Hi Arumugam,

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

Leo Laohoo
Hall of Fame
Hall of Fame

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.

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?

Thanks for the tips, didnt think of that. Will try to locate any Dell machines.

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

hi,

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

2w4d: %IP-4-DUPADDR: Duplicate address 192.168.113.2 on Vlan113, sourced by 001f.6c88.4dff

so I shut and noshut vlan 113,

now I am geting ,

2w4d: %IP-4-DUPADDR: Duplicate address 172.16.176.2 on Vlan196, sourced by 001f.6c88.4fff

Can anybody help me?

Thanks

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.

I had the same problem and I was able to identify it and resolved the issues.

*Mar 1 04:25:07.417: %IP-4-DUPADDR: Duplicate address 192.168.2.2 on Vlan1, sourced by e4b9.7a7f.6f0e.

I traced the IP address on the devices that were connected on the switch and figured my laptop has the same IP address shown here. So, I changed the static IP on my laptop and that fixed the issues. 

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