Arp issue with Cat6509

Unanswered Question

I have a catalyst 6509 Sup720 MSFC3 12.2(14)SX2

I have just deployed a new windows 2003 server which is a guest OS on a VMware ESX 3.2 server. Intermitently I lose connection to this server from other VLANs on the 6509. When I do a show arp | include <server ip> I get a differnet value during the period I have lost connection as opposed to when I have connection. Connections that do not go via the 6509 (ie VPN direct into the VLAN) do not have any issues.

I have seen this behaviour once in the past but did not have time to torubleshoot it and the server causing the issues was retired.

Any Ideas?? this does not seem to be a VMware issue as I have 31 other VM's on the same server configured the same way and they are all working 100%

There does not appear to be any consistency between failures as sometime it is once an hour and sometimes more frequently however all failures seem to be about 60-65 pings..

darn confusing.

Thanks for your help


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lgijssel Wed, 10/10/2007 - 10:27
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This is funny because the symptoms you describe are in fact typical for a duplicate ip adress....

However, normally Windows notices you in this kind of situation and this does not seem to be the case here. Are you sure there are no messages pointing in this direction?



lgijssel Wed, 10/10/2007 - 10:46
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OK, that might be a VMware issue.

To troubleshoot this issue, you should look up the rogue mac in the cam table as it pops up. In that way you can locate the physical port where it is sitting. If this does not match the port where the other server is you have a duplicate ip. (if not, that's for later)

One way or the other, you need this info to continue the troubleshooting process

If possible, shut down the server for a moment, clear the arp table and ping the ip adress. If there is still a response you have a dupicate ip indeed.




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