Re: AP541N - Can't get an IP address on some devices.

broonster · ‎05-30-2012

Hi There,

I have an AP541N-N-K9 Dual Band Access Point which I'm having some issues with. We have a few users with Android and iOS devices and they want to connect to our corporate network but when we configure the wireless network details in both OSs none of the devices get an IP address. We have an MS AD/DNS/DHCP infrastructure. On looking at the logs of the access point I can see the devices successfully authnticating but then I see the connection being disassociated and deauthed. A few seconds later the device attempts to get an IP address again and the same thing happens again. This loop just keeps on going forever. If we connect to the AP with an MS OS everything is fine. Below are examples of the logs.

May 31 14:29:46	info	hostapd	wlan0: IEEE 802.11 Assoc request from 1c:ab:a7:ad:77:bb BSSID 00:21:29:00:cb:60 SSID IHCNAT
May 31 14:29:46	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb deauthed from BSSID 00:21:29:00:cb:60 reason 3
May 31 14:29:44	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb disassociated from BSSID 00:21:29:00:cb:60 reason 8
May 31 14:28:44	info	hostapd	The wireless client with MAC address 1c:ab:a7:ad:77:bb has been successfully authenticated.
May 31 14:28:44	info	hostapd	wlan0: STA 1c:ab:a7:ad:77:bb WPA: pairwise key exchange completed (WPAv2)
May 31 14:28:44	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb associated with BSSID 00:21:29:00:cb:60
May 31 14:28:44	info	hostapd	wlan0: IEEE 802.11 Assoc request from 1c:ab:a7:ad:77:bb BSSID 00:21:29:00:cb:60 SSID IHCNAT
May 31 14:28:44	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb deauthed from BSSID 00:21:29:00:cb:60 reason 3
May 31 14:28:42	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb disassociated from BSSID 00:21:29:00:cb:60 reason 8
May 31 14:27:42	info	hostapd	The wireless client with MAC address 1c:ab:a7:ad:77:bb has been successfully authenticated.
May 31 14:27:42	info	hostapd	wlan0: STA 1c:ab:a7:ad:77:bb WPA: pairwise key exchange completed (WPAv2)
May 31 14:27:42	info	hostapd	wlan0: IEEE 802.11 STA 1c:ab:a7:ad:77:bb associated with BSSID 00:21:29:00:cb:60
May 31 14:27:42	info	hostapd	wlan0: IEEE 802.11 Assoc request from 1c:ab:a7:ad:77:bb BSSID 00:21:29:00:cb:60 SSID IHCNAT

Any ideas?

alepatte · ‎06-22-2012

Hi Craig,

Thank you for contacting Cisco Small Business Forum.

I have a few questions.

- what firmware this AP is on? Here is the link that you can verify that you have the latest on:

http://www.cisco.com/cisco/software/release.html?mdfid=282790482&flowid=6790&softwareid=282804210

- How manu devices have this issue?

- Do you run a clustering, if you have only one AP then you do not need clustering.

- What channel do you use? If you have "auto" you might consider to change to specific one. Keep in mind that only 3 non overlapping channels:1,6,11. So, choose one of those.

- what security settings do you have on the AP? Do your Android devices support that?

Sincerely,

Alena Patterson

Cisco SBSC Engineer

CCNA

broonster · ‎06-27-2012

1. Our firmware is 2.0.1.

2. We only have the one device (so no clustering).

3. We use channel 2.

4. We are using WPA personal with the SSID hidden and no MAC filtering.

Arturo Bianchi · ‎06-26-2012

Hi,

have you noticed if, by chance, a cold reboot of the AP temporarily solves the problem? On some AP541 matched by a similar problem that blocks certain devices while others continue to work! This is the thread that I started but we have only the "reason 3" message.

73,

Arturo.

alepatte · ‎06-26-2012

Hi Arturo (bianchi),

Thank you for your reply.

As a previous engineer mentioned to you the reason 3 means that the station is disassociated.

By looking at the above logs, the reason 8 comes first. The reason 8 means "Operating System moved the client to another access point using non-aggressive load balancing."

My question then, what is your network topology? How are your devices connected in your network. How many APs do you have, are they PoE, are they in cluster, etc?

We need a bit more info before we can see what could be a reason for this issue.

And again, you can call us at any time for the support at 1-866-606-1866 and any available engineer will be able to assist you.

Sincerely,

Alena Patterson

Cisco SBSC Engineer

CCNA

broonster · ‎06-27-2012

As stated above, we only have a single AP and it is PoE. The AP is connected to a Linksys SFE2000P PoE switch.

Also, when we configure the devices with a static IP address they can successfully connect to the Cisco AP which might suggest an issue with DHCP. MS devices are still getting an IP address from DHCP when conecting wirelessly with the AP however.

broonster · ‎06-27-2012

Cold reboot was of no help unfortunately.

alepatte · ‎06-27-2012

Hi Craig,

Thank you for your reply.

The firmware that you have is not the latest one. The latest on is 2.0.2. Here is the link to the firmware upgrade.

http://www.cisco.com/cisco/software/release.html?mdfid=282790482&flowid=6790&softwareid=282804210

The new f/w did fix few issues with DHCP.

Also, as I mentioned before, you should have only non overlapping channel on your device 1,6 or 11. Anything else will cause interference. So, may I suggest you to change your channel to 1 or 6 or 11.

Hope that helps.

Sincerely,

Alena Patterson

Cisco SBSC Engineer

CCNA

broonster · ‎06-27-2012

It says here

http://www.cisco.com/cisco/software/release.html?mdfid=282790482&flowid=6790&softwareid=282804210

if I apply this firmware I have to manually re-configure the device again. Is there no way to avoid this?

alepatte · ‎06-28-2012

Hi Craig,

You do not have to reconfigure your device manually after the firmware upgrade.

Make sure that you have a back up of configuration before you do f/w upgrade.

Once you did firmware upgrade, just monitor your network. If you still have some issues, then I would suggest to do factory reset of your device (hold reset button for 45 sec with power on) and then reconfigure it manually.

Hope that helps to answer your question.

Sincerely,

Alena Patterson

Cisco SBSC Engineer

CCNA

nasa_dork · ‎03-29-2013

I had this exact same problem and have read over most of the posts about it with no success. two commands fixed my problem instantly.

My network: Cisco switch, providing DHCP, VLAN, PoE, switchport trunk to AP. AP541N providing wireless for multiple VAPs, PoE, switchport trunk to switch.

All PCs, Macs, Wireless Bridges, mobile devices, internet enabled dvd players - all connect to the AP and get an IP address without problem. My wireless thermostat however does not. It connects, associates, but does not get an IP address. The AP sees it, the switch sees its MAC address in its table, but no DHCP. I see the Reason 3, Reason 8, etc messages in the AP like others have mentioned.

I had previously added a ip broadcast-address setting to the VLAN, but I added the ip helper-addresspointing to the DHCP server (which was the same switch, so it equalled the router address / default gateway for the subnet.). This still did nothing.

I added the global command "ip dhcp limited-broadcast-address" and the next time my thermostat tried to connect it received an ip address. I removed this command, rebooted the switch and AP, and it stopped working. Re-added it and again, instant IP address for thermostat.

Other posts have talked about other devices as the DHCP server, I remember Sonicwall as one of them. I did a quick google search on the "limited broadcast address" and it appears those devices have a configuration to support IP Helper / Limited Broadcast configuration as well.

This is what solved the problem for me. Hope it helps others