Airespace Wireless Client periodically unable to obtain DHCP

[tschaffran]

I am experiencing a problem at a couple of customer sites. I have the WLC configured to point to a Microsoft DHCP server. Periodically, all of the clients will be unable to obtain a DHCP address. Currently, the only fix I have been able to come up with is to reboot the WLC. Obviously, this is not the desired solution. Has anybody experienced this problem and been able to permanently fix it?

[scottmac]

What version of the OS and client software are you using?

Have you done a bug check on CCO?

On the clients, are you using the vendor's client software, or MS Zero Wireless Config?

Let us know

Scott

[tschaffran]

I have not done a bug check yet. The cleints are using the windows wireless client.

[b.goodenough]

I have the exact same problem. The 4404 passes the DHCP addresses from the DHCP server to the clients until it just stops. The clients appear to be connecting, but then return an error of "this connection has limited or no connectivity". That is my sign to go reboot the controller. There isn't a bug listed for it yet and I need a patch or fix if anyone has it. Thanks!

[td3tsu]

We encountered the same issue and were told by Cisco TAC to use the local DHCP server. The engineer said it was a bug that should be fixed in January.

[jdominquez]

I am having the same problem and this is the bug CSCse79793.

[serg_russ]

i too

and when i put comm 'sh dot ass'

i see a next screen

---------------------

0004.6147.a875 172.16.3.236 unknown - self As

c

0004.6169.de1f 0.0.0.0 unknown - self As

c

0011.95c3.9b91 172.16.3.150 4500-radio - self As

[serg_russ]

0004.6169.de1f 0.0.0.0 - no IP address

[serg_russ]

and again

i have just one AP1231G, but my problem same too - wireless clients not obtaining IPs periodic from external DHXP server (freeBSD)

With wired clients working good

[b.goodenough]

Hi folks,

I talked to the TAC and they said this is an issue with 4.0.187.8 and they are working on a fix. The alternative is to use the internal DHCP server on the controller. That isn't an option at this client, yet; but I am looking forward to a fix as this is quite frustrating to reboot randomly to fix it.

[magress]

The correct bug id is CSCsf32185 and we are currently working with development on a fix. If anyone can obtain the following it would help speed up resolution in the matter (please open a TAC case and report the issue):

1) Captures of all traffic on the network during a successful DHCP transaction.

2) Output of 'debug dhcp all' for the same transaction.

3) Captures of all traffic on the network during a failed DHCP transaction.

4) Output of 'debug dhcp all' for the same transaction.

5) Description / diagram of the network(s). I.e. what vlan the client

Thanks,

Mark

[zhenningx]

Hi Mark,

Is the bug CSCsf32185 fixed in 4.0.206.0?

Thanks,

Zhenning

[MICHAEL SCHROEDER]

Hi Folks, i had the same problem a few days ago with 3750 WLC Integrated Platforms with SW Rel 4.0.206.0. It seems not to be fixed yet. Regards, Michael

[alex.hoang]

I am having this problem as well. I have 3 WiSMs running 4.0.155.5 version of code and have intermittent dhcp issues. Does anyone know if the fix is yet available?

[Darren Ramsey]

The bug toolkit does not show that being fixed yet. However I have a workaround that might help. We have 5 4404 and 3 WISM and experienced the DHCP issue from time to time. Once the DHCP fails, the only way to remedy is a controller reboot.

I noticed the controllers "proxy" the DHCP request by default instead of an IP helper type relay. You can differentiate this by examining an IPCONFIG /ALL from a wireless client. In proxy mode you'll see the controller's virtual address as the DHCP server. In non proxy mode you will see the actual external DHCP server as the client's DHCP server. You can modify the proxy behavior with "config dhcp proxy disable". Now I'm not making any promises, but I've not had the DHCP issue since I made the change. It could have alleviated the issue or maybe I've just been lucky. It might be worth a try. Post back if this helps. No doubt many of us are having this issue.