Connection over WLC does not work

[RobinD]

Hi guys

I have a problem with my WLC2504. I have two running WiFis in different VLANs. Now, I created a third wireless in a own VLAN with the adapted preferences adjusted for the new VLAN. Everytime I connect a device with the Wifi, I don't get any connection because I get an APIPA address. I have an external DHCP server running.

I thought there may be a problem or a missing configuration on my switches between, but thats not the case. I patched a LAN port into this VLAN and it worked fine. Therefore it must be a missing configuration or wrong configured setting on the WLC. Does anyone comes up with a solution? If necessary I can upload the config.

Greetings

Robin

[jeetkulkarni]

Under CONTROLLER > INTERFACES> "relevant interface for the ssid"> have you specified the DHCP servers? Are they pointing to the correct ones. Does the Wireless LAN controller have direct access to the DHCP server?

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[Deepak Kumar]

 Hi, 

You have two option to handle the DHCP broadcast/request packet from Cisco controller. 

1. DHCP PROXY ENABLED: Enable the option and put the DHCP Server IP, so the controller will convert a packet from broadcast to unicast and forward to DHCP server. 

2. DHCP PROXY DISABLED:  If DHCP Proxy option is disabled then packet goes to AP manager default gateway, means SVI IP of your switch and You need to configure the IP helper address on SVI interface. 

For configuration the DHCP option please follow below steps:

1. Login in WLC and Select SSID (WLAN) and click on Edit

2. Open Advanced tab menu and enable the feature DHCP Server Override and Put the DHCP server IP address. 

https://www.cisco.com/c/en/us/support/docs/wireless/4400-series-wireless-lan-controllers/110865-dhcp-wlc.html

And I got an additional information from a support form:

If DHCP proxy is disabled, if you fill in a DHCP server or not, it won't be used.

The request doesn't come from the AP manager. The wireless client broadcast will leave the controllers interface for that vlan (WLAN tied to controller interface) for the GW. The GW will then forward to DHCP if helper is enabled.

https://supportforums.cisco.com/t5/getting-started-with-wireless/dhcp-ip-helper-in-wireless/td-p/2610053

Regards,

Deepak Kumar