Wireless clients sporadically getting Limited Connectivity, APs dropping packets

[John_Rowler]

We have a pair of V2110 wireless controllers and around 400 3825i access points. Controller firmware is 09.21.06.0002. AP firmware is 9.21.27.1387X.

About 4 months ago we noticed a problem where the APs would just drop traffic. A packet capture will show a ping coming into the radio from the client, going out the Eth interface on the AP, the reply coming back into the Eth interface, and never going out of the radio.

A particularly strange detail is that this only happens with certain source/destination traffic. For instance a client cant ping the gateway of 10.1.20.1/24. but cannot pint the server at 10.1.20.2. Since we can see the ping making it to the server and the ping reply making it back to the AP, we know it's not a firewall/ACL/routing issue on any other part of the network. The traffic disappears at the AP. Clients cannot communicate with anything on the Internet or any of our servers (DNS, DHCP, etc.) during this time. They can ping gateways in any subnet but that's it; everything else is failed.

More details:

-We've gone through several firmware updates with GTAC. Nothing has helped.
-The issue can affect any client on any AP in any location at any time.
-The issue is intermittent; it may happen every few minutes or once per month to a particular client in a particular area. Once failed it may last for seconds or days.
-While it's affecting one client, other clients on the AP may be working fine or may also fail.
-It can happen on either 2.4 or 5.7GHz.
-It can affect any type of client (phone, laptop, tablet) and any OS.
-Restarting the client or AP will sometimes fix the issue, sometimes not.
-It happens with our without using NAC, or any other type of authentication. It happens on completely open networks as well.
-It happens on both bridged at AP and bridged at controller topologies.
-It's not limited to a particular subnet or VLAN.
-It happens with or without Flexible Client Access enabled.
-It happens on either controller.
-GTAC hasn't made much progress on the issue in 4 months.

[Rey_Juan_Carlos]

Hi Doug, I can't understand why do you recomend in DCS (Dynamic Channel Selection) "Monitor mode" (If needed enable for 60 mins and lock down).
I think that this function would be Active Mode by default, because if you have to put more APs inside the infraestructure you don't have to config DCS.
When you have a lot of APs this is not functionality.

[FES]

Hi, in 9.21.08 we still have clients that are conected to 801.x wlan but have limited conexión. If we turn off wifi interface and reconect it we hace conexion again...
Anyone more has this behaviour?

[FES]

I have reached one problem wirch the four way handsake and the radius configuration in the controller.

https://gtacknowledge.extremenetworks.com/articles/Solution/Wireless-Clients-are-getting-disassociat...

Otrherwise, we algo find other issue in windows 10 supplicants. The name os the trustes radius in the supplican have to match with the principal name of the certificate in the radius server. I mean, the dns name of the server cant be a alt-name in the certificate.

[JP4]

Yes, when we were on straight 9.21.07, we still had problems, but like I said, we seem to be an improved state right now with a combination of things. We are nearing the end of our school term so we are continuing to monitor. Just don't want to make the situation worse at a bad time.

[FES]

good, you should review the solved issues in 08 because two of this issues are problems with radius and just with your connectivity problems. Somebody of support in other post said that the release is stable and only solve detected problems.
We are planing to upgrade this weekend, because we have a lot of users that sporadically have no connection and they can't connect to our 802.1x wlan.
Otherwise de options at Privacy tab and the upgrade from 3 to 5 tries in radius server authentication configuration, have solved connexion problems from some users.
good luck, and reply if you improve the connectivity.