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Broadcom NIC Teaming and Cisco WLC Incompatibility - Disable Gratuitous ARP Possible?

We are installing a new Cisco 2106 WLC with a LWAPP and have ran into an issue. Essentially every server that is running NIC teaming on Broadcom ethernet ports responds with a duplicate IP address message due to a gratuitous ARP response that is invalid.

(see this issue... )

Pretty much any computer that is requesting an IP via the WLC gets a duplicate IP address message and if you run wireshark you can see the reason is because every computer using NIC teaming responds poorly to the GARP. Wireshark message shows as "Gratuitous ARP for X.X.X.X (Request) (duplicate use of X.X.X.X detected!)."  This appears to happen when using the WLC local pool and doing DHCP relay to a dedicated DHCP server. Clients are Windows of all flavors and MacOS.

According to the link above, I need to update my Broadcom drivers. I will happily update the Broadcom drivers, but at this point its impossible without scheduling down time (can't this time of year). So in the meantime, I would like to see if anyone has a work around for this. I also am getting the question of "why hasnt any other wireless access point that we've ever used not had this problem, including $20 ones" and its hard to answer. 

I looked into disabling the GARP messages from the cisco WLC, but the normal Cisco IOS command for that doesnt work (as far as I can tell). In Cisco IOS, its just issuing a "no ip gratuitous-arps"  command.

So with that said, does anyone have any suggestions or do I need to provide additional information?



Cisco Employee

Re: Broadcom NIC Teaming and Cisco WLC Incompatibility - Disable

There is indeed no feature to disable gratuitous ARPs.

We are clear that in this case, the problem is not on Cisco side right ? So there is little pressure to have this kind of feature implemented in future releases.



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