topic Re: Wireless Clients dhcp request in Wireless

Wireless Clients dhcp request

Suresh Varghese — Sun, 04 Jul 2021 03:15:43 GMT

I have 2 sperate DHCP servers installed at my office.

One is hosted in a cluster enviornment and the other is on a single seperate windows server.

Both my LAN and wireless clients are getting DHCP IP from the single server

But only my LAN clients are getting IP from the cluter server scoped DHCP, wireless clients are not able to get IP.

I have added the following commands on

Commands added under vlan 1 interface on gateway router

ip helper-address XX.XX.XX.XX (windows cluster virtual server IP)

ip helper-address XX.XX.XX.XX (windows stand-alone server IP)

Command added globaly on the gateway router

ip dhcp smart-relay

Can anyone let me know what could be the issue?

Many thanks in advance

Re: Wireless Clients dhcp request

Nicolas Darchis — Tue, 31 May 2011 09:27:30 GMT

You should maybe precise what wireless equipment you have ? Controller ? IOS ? Router with wireless interface ?

Re: Wireless Clients dhcp request

Suresh Varghese — Tue, 31 May 2011 10:44:16 GMT

I have a cisco WLC 2125 controller, Model No AIR-WLC2125-K9, ver 6.0.199, with an uplink to my gateway 4507 CAT switch connected to a 2851 router having 1 serial interface and 3 gigabit interface.

I have an additinoal subnet configured as the secindary ip on interface vlan 1 on the 4507 CAT switch.

This subnet acts as one of the DHCP ranges for which smart-relay has been enabled on the 4507 switch.

Now my primary subnet on the vlan 1, 10.101.0.0/22, of which 10.101.3.0/22 is configured as the seciond dhcp range.

I hope i have made my scenario clear.

Please do let me know if you have any clarifications.

many thanks

Re: Wireless Clients dhcp request

Nicolas Darchis — Tue, 31 May 2011 10:50:11 GMT

If you have a WLC then ip helper is not needed. You should enter your DHCP servers ip addresses in the interface configuration of the WLC (the interface used for the WLAN).

The WLC will be the one doing dhcp proxy.

Except if you disabled the dhcp proxy behavior of the WLC in which case, the ip helper on the gateway of the client will be required.

Hope it clarifies

Re: Wireless Clients dhcp request

Suresh Varghese — Tue, 31 May 2011 10:59:03 GMT

Well the thing is that the uplink from my WLC to the 4507 is configured as a trunk port for carrying both the corporate and guest SSID which are on different subnets.

I checked the WLC config and it is as attached

Now if i enable the DHCP server, which subenet do i add there or can i add multiple dhcp servers

the secondary subnet 10.101.10.0/24 is working for both LAN & wireless clients but for some reasom the subnet 10.101.3.0/22 is working only for LAN clients.

Thanks Nicolas

Re: Wireless Clients dhcp request

Nicolas Darchis — Tue, 31 May 2011 11:03:29 GMT

You didn't understand.

Step 1) Click on your SSID. The first page should tell you what interface the ssid is linked to. Normally you created a corporate vlan interface and a guest vlan interface.

Step 2) Go on "controller", "interface" and select the according interface

There you have 2 fields to enter DHCP server. Enter your DHCP server ip addresses.

The ip that will be given to the clients is an ip of the subnet of the WLC interface sending the request.

The fact that your uplink is trunk has no relation to this at all and the "advanced" tab of the wlan config either

Re: Wireless Clients dhcp request

Suresh Varghese — Tue, 31 May 2011 11:12:34 GMT

Sorry Nicolas, i had got confused.

I did the changes and paused the first subnet and it started recieveing IP from the second range.

Many thanks brother....