Troubleshoot CIsco WLC with External DHCP Server

[happyatuni]

Dear NetPro gurus,

I'm a Cisco WLC newbie and one of my client currently faced the following issue:-

They have 3 x Cisco WLCs in the same cluster where hundreds of CIsco APs all homed back to these 3 x WLCs.  And they have multiple SSIDs advertised by the APs.  The problem is that the wireless clients (i.e. iPhones, iPads & laptops) sometimes takes a "very long time" to get their DHCP IPs (regardless of which SSIDs).  Sometimes they managed to get IP, sometimes they don't.

All the wired PCs get their DHCP IP via the same external DHCP server without any problems.

Is there any "debug commands" i can use to further troubleshoot this? Or any good place i can start to troubleshoot this?

Would greatly appreciated if anyone can shed some light on this.

Cheers,

Lee                  

[Stephen Rodriguez]

Debug client < client mac address >

would be a good place to start.  it will show you the authentication, and the DHCP traffic flow.

That being said, what mode are the AP in Local or FlexConnect/HREAP?  If they are FlexConnect, and you are doing local switching in the WLAN, then you need to make sure that the port the AP is connected to is a trunk port.

If they are local mode and all traffic is backhauled to the WLC, then an access port is fine.  If they are local, how many ports are connected?

HTH,
Steve

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[Saravanan Lakshmanan]

Also enable, debug dhcp message enable with debug client.

Are Interface group enabled.

Are dhcp proxy enabled or disabled.

Are fast ssid enabled.

Is it guest anchor setup.