CSM reporting failed ARP request

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Jun 7th, 2007
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We have a CSM on Catalyst 6509 SUP720, the IOS is 12.2(18)SXD7b.

We have a problem with load-balanced portal servers with the CSM. Checking Catalyst log we see the following messages:

Jun 7 06:17:42.145 UTC: %CSM_SLB-6-RSERVERSTATE: Module 4 server state changed: SLB-NETMGT: Server [ip address] failed ARP request

Jun 7 06:17:43.505 UTC: %CSM_SLB-6-RSERVERSTATE: Module 4 server state changed: SLB-NETMGT: Server [ip address]now responding to ARP requests

Jun 7 06:19:23.445 UTC: %CSM_SLB-6-GATEWAYSTATE: Module 4 gateway state changed: SLB-NETMGT: Gateway [ip address]failed ARP request

Jun 7 06:24:12.241 UTC: %CSM_SLB-6-GATEWAYSTATE: Module 4 gateway state changed: SLB-NETMGT: Gateway [ip address]now responding to ARP requests

At the begining, the message were on refer to failed ARP for the real servers, but now the CSM reports failed ARP request on the Gateways (Vlan Interfaces) too.

Any idea?? We don?t now if the problem is the network, or is the CSM Card or the IOS version.

The Catalyst 6500 is on Distribution Layer, connecting 4 Access switches (Enterasys) and 2 Core Cat6500 switches. The balanced servers are on a Access Enterasys N7 Switch.

Thanks in advance...


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Overall Rating: 3 (1 ratings)
tprendergast Mon, 06/11/2007 - 11:43
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What version of software are you running on your CSM?

I've had the real server ARP issues before, and that is really nothing to be worried about. It is more of an informative message. Are you experiencing issues with the gateway arp message relative to traffic being dropped or blackholed?

If not, it may just be more of an informative message than anything.

PEDRO AGUIRRE Mon, 06/11/2007 - 13:28
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Hi Tim, thanks for your reply.

Yes, we are experiencing issues with gateway ARPs. In fact, this is the reason because we think there is a problem with the Card.

I tried to configure a "dummy serverfarm" without success.

The software version on CSM is 4.2(2)

Have you any recomendation to solve this problem?



tprendergast Wed, 06/13/2007 - 13:11
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Try rolling back to 4.1(9).

There are some known issues with 4.2 (it's a feature branch, not a fully stable branch).

That would be my recommended course of action. If you still have the same problems, then you may wish to open a TAC case to see if they can debug why the arps are failing.

How often does the gateway fail the arp? (how long between messages in your show log?)

PEDRO AGUIRRE Fri, 06/29/2007 - 07:08
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Hi Tim

Two weeks ago we made a change on Cat6500:

- First we moved the CSM to another Slot, the configuration was deleted and we configurated a very basic balancing configuration. The result was the arp?s failed and gateway failed. This ocurred few minutes after

- Second, we installed a new CSM on the same Cat6500. The result: al is working fine!!

We are going to report the Card as a fail HW to the service support in order to have a replacement.

Thanks for your time!!



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