C9800-L-F-K9 ARP Issue

[wilfredj]

Hi All

We recently deployed a 9800 in our environment and we are seeing some client to client connection issues.

We have one SSID set up for dynamic VLAN assignments which has a VLAN assigned to the policy which doesn't route anywhere.

The other SSID is set up with the client VLAN assigned to it in the policy.

The dynamic VLAN assigning is working correctly on the first SSID but the only issue is that wireless clients aren't able to communicate with each other even though they are in the same VLAN. These clients are however able to communicate with clients that are on the other SSID who are in the same VLAN.

I enabled ARP broadcast on the VLAN that the clients are landing in but that only fixed the communication between clients that are on different SSID's not on the same SSID.

The controller, switches and wired clients are able to ping all wireless clients without issue.

The WLC is uplinking to a C4500X and WLC software version is 17.6.4

[Flavio Miranda]

Hi @wilfredj 

Can you share the command output of show wlan id <id> ?

[wilfredj]

Hi @Flavio Miranda 

As requested the outputs are attached.

So dynamic VLAN SSID client to client communication not working but is able to communicate with clients on static VLAN SSID, static VLAN SSID client to client communication working and is able to communicate with clients on dynamic VLAN SSID.

[Flavio Miranda]

@wilfredj  there is a feature on the WLC that can cause this behavior. The feature is called  "Peer-to-Peer Blocking Action : "

As per the description,  It seemed that you could have one SSID with the feature enable and disable in the other. But, checking the config, both SSID is actually disabled.

 Sounds to me like some bug. If you have the chance, I would engage TAC to take a look.

[Leo Laohoo]

Raise a TAC case and get them to check if this is CSCwh12413.

[wilfredj]

Thanks for the info guys will engage with TAC and hear if they have a solution for it.

Will also post updates here

[wilfredj · Accepted solution]

Apologies for replying to such a old post but thought I would finally give an update to the issue I had here.

Turns out upgrading the firmware from 17.3 directly to 17.9 isn't such a good idea. Downgraded the firmware back to 17.3 then upgraded it to 17.6 then up to 17.9. No issues after that

Note to self follow the upgrade path

[MHM Cisco World]

We thanks to you alot 
because you update us 
have a nice summer 

MHM

[Rich R]

Yes @wilfredj  that's normally covered in the release notes so always worth checking.
https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-9/release-notes/rn-17-9-9800.html#Cisco_Concept.dita_59a2987f-2633-4630-8c7b-a8e8aecdeaf7
Which 17.3 release did you try to upgrade from and what APs do you have?