AP not forwarding DHCP packets?

[JonLindahl]

I have a small test network with Mobility Express set up. The network consists of three switches, three AP, a firewall and DHCP-server.

AP models is 1832i, 3802i and 2702i. ME controller is either the 1832 or the 3802.

There is one SSID with VLAN tagging, L3 terminated on the firewall. The firewall is set up with DHCP relay to a different VLAN with DHCP server.

After random time, the clients connected to the 2702 APs loose DHCP lease, and cannot renew. The DHCP server does not see any requests from the clients. If I down the switch-port to the AP forcing clients to roam to another AP, the DHCP requests is forwarded again, and the clients get new lease.

After reboot of the 2702 AP, the clients works random time again - weeks or maybe months - until suddenly the 2702 stops forwarding DHCP packets again.

I have verified the firewall and switch configuration - all ports to AP is configured the same, and moving the 2702 AP to another switch does not solve the problem. Neither does upgrading the APs to another release - now running 8.10.183

Any suggestions?

[Mark Elsen · Accepted solution]

  - Probably some long time resource exhaustion , client debugging may provide some insights (at the time the problem is happening), but can not resolved it (indeed) . You may want to configure global ap syslogging and or attach a permanent console to a 2702 AP to get insights (if possible).

 M.

[JonLindahl]

I feared it might be something like that - I think the best solution for me will be to just retire the AP and replace it with a newer model. It might be that an older release would work better on this AP, but the other two works just fine with the latest release. The inconsistent and long time period between crashes makes it a pain to troubleshoot further.

Anyways - thanks for your reply!

[Rich R]

In the meantime work out what the longest time the AP works for and do a scheduled reboot often enough to make sure it never gets to that point.  2700 AP went end of software maintenance in 2020 https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-2700-series-access-point/eos-eol-notice-c51-740711.html so they are generally not fixing any more bugs for those.  Sometimes you get lucky and pick up fixes that they've provided for IW3702 because they run the same code and those are maintained till Aug 2024.