Wrong IP address being assigned to wireless clients

[murraymwps]

I have a WiSM controller on a 6509 running 7.0.235.0. 

Clients are being assigned an IP address on the wrong controller interface. I have an AP group with a WLAN configured with an interface with IP 172.22.64.5/20 (Vlan 44). Clients are being assign IP addresses via DHCP server on the subnet (Vlan 34) configured on the interface in the "Interface/Interface Group(G)" settings under the general WLAN configuration.

When I do a packet capture I see packets being forwarded to the DHCP server from the controller sourced from the Vlan 34 interface instead of the Vlan 44 interface.

Screenshot attached shows the AP group configuration. The "ws-secured" interfaces is the Vlan44 interface.

I have an ticket opened with Cisco but thought I'd throw this out here too.

[michael o'nan]

Would VLAN34 be the assigned management IP address on this controller?

[murraymwps]

No, management IPs are Vlan31. Vlan34 is the global interface for this particular WLAN. I'm trying to change that via the AP group configuration. Basically I've been running with this WLAN with one subnet for 5 buildings. I want to keep the SSID the same but configure unique subnets per building so I'm creating AP groups per building. Within each AP group I configure the unique controller interface but clients are still getting IP addresses on the subnet of the global interface of the WLAN.

[rsaeks]

Is the AP in Local or FlexConnect mode?

If it is in FlexConnect Mode, you can use a variety of methods to map the WLAN to a specific VLAN.  (Select the AP > FlexConnect Tab > VLAN Mappings, or use FlexConnect groups)

[murraymwps]

Local mode

[moh_setan1988]

Hi,

Can you please do "debug client <client MAC Addreess> " on the controller CLI, then try to reproduce the issue with the same client that you are debugging, and then paste the outputs here?

Also can you please provide the configuration of the interface that you are configuring your WLAN to, and make sure that the AP that you are connecting to is a part of this AP group and not any other groups?

Kind Regards

Mohammad Setan

[murraymwps]

The issue has been resolved. The configuration was correct and the behavior is actually expected. Here's the explanation from Cisco TAC:

"This is a normal behaviour as you make the change on WLC, clients will not disconnect and ask for the new IP as WLC will keep the clients connectivity without interruption till it is disconnected and a new session starts. Also clients will always ask for the same IP it was connected to but as soon as it will ask for, DHCP server will ignore the request. So client will request for new IP for the Vlan it is being configured, DHCP allows then."

Basically after making the interface change in the AP group clients will still retain their old IP address even through new AP associations instead of requesting a new one with the new interface. After a weekend of expiring DHCP leases and disconnected clients they pulled the correct IPs.