WAP561 - DHCP issues

sebastian.angerer · ‎11-12-2015

Dear all,

we are using two clustered WAP561 operating with two radios (one at 2.4 GHz and one at 5Ghz). Both operating on Firmware 1.2.0.2. The wireless clients obtain their IP via DHCP (Win2012).

From time to time we are having the issue (typically, but not only, after an uptime > 3-5 days) that clients do not get an IP address assigned and hence do not connect properly to the Network. We have traced this with packet analyzers. The clients send DHCP Discover messages and the Server answers correctly with DHCP Offer. The DHCP Offer does arrive at the WAP, but the client never receives it - hence sends the next Discover.

We were hoping that 1.2.0.2 solves this for us (according to release notes an issue "CSCus23303 - Wireless Client cannot get IP from DHCP Server" has been solved), but seems in our configuration the issue still persists.

Any suggestions what might cause this or how to resolve this?

Thanks in advance,
Sebastian

Eric Moyers · ‎11-12-2015

My name Eric Moyers. I am an Engineer in the Small Business Support Center.

I am sorry to hear that you are experiencing this issue. I know that what I am about to suggest has assisted customers before woth similar issues. I would try this and if that does not improve your situation then I would call and open a case to work speak with one of our the engineers.

In the new firmware 1.2.0.2, there is an option MFP under the SSID if the unit is using "N" speed. We have found disabling this feature has resolved quite a few disconnect issues.

The way to set this to "Not Required" is to:
This option is located where you configure the SSIDs (so Wireless->Networks then there's a link under each SSID to "Show Details"), but it ONLY appears if you disable WPA-TKIP.

If it is set to "Capable" (the default) then the WAP will expect clients that advertise they support it to have to use it. If set to “Required” then only wireless clients that can use PMF will be allowed on this SSID. If set to “Not Required” – self-explanatory. I would set this setting to “Not Required”

If your customer needs TKIP enabled, just disable it first, make the change for MFP, and then set TKIP back to enabled.

I would do this for both radios.

If this does not improve your issue, please call our support center and open a case so that one of our engineers can work directly with you.
http://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html

Eric Moyers
.:|:.:|:. CISCO | Cisco Presales Technical Support | Wireless Subject Matter Expert

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sebastian.angerer · ‎11-12-2015

Hi Eric,

thanks for the hint! We will try that and create a case if it does not resolve the issue.

Sebastian

chrisklemm · ‎12-07-2015

Just tossing a note out that we are also still experiencing the same issue with 1.2.0.2 - I have made Eric's suggestions as well. I have 3 customers experiencing this, each with 5-7 access points, a very simple infrastructure and a Windows DHCP server. very frustrating.

sebastian.angerer · ‎01-13-2016

@chrisklemm: Are you able to reproduce the issue and can take package traces respectively? If so, it would be great if you can get in touch with me. Seems support team needs further examples.

Thanks,

Sebastian

chrisklemm · ‎01-13-2016

It would take me some time. 2 of the 3 customers I referenced have switched their entire wireless infrastructure to a different brand. I physically have 5 of these problem units in my possession, but will have to make time to prepare for testing/documenting the issue.

sebastian.angerer · ‎01-18-2016

Ok, too bad. I currently have a hard time reproducing the issue for further traces requested by support and seems they will soon close the case if I can't. Hence trying to find further examples so they have a chance to get to the bottom of this as this seems happening not only for us.. Very frustrating after more than two months ticket ping pong with them.

stevep1969 · ‎02-17-2016

Hi Sebastian

Did you manage to get a fix from Cisco?

We are experiencing the same issues. I have applied the `fixes` noted here.

sebastian.angerer · ‎02-17-2016

Hi stevep1969,

unfortunately the issue seems tricky and the ticket is still ongoing. One challenge is also that the problem is not constantly happening and hence it often takes time until I can provide Cisco with the traces they require.

@Cisco Team: If somebody is still following this thread - there seem to be more and more people with the same issue - chrisklemm had 3 customers, stevep1969 does face the issue and browsing the web there seem to be others as well. Not sure there is an option to take this into consideration and extend my case with information from others to find the patter more quickly, but I guess this would be very beneficial.

BR,

Sebastian

sebastian.angerer · ‎11-16-2015

Unfortunately the issue still persists. Thanks for the hint though. I have created case 637143161.

BR,

Sebastian