WLC and IP helper without gateway

Unanswered Question
Mar 20th, 2014
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I have a WLC 5508 with a management IP interface (

I've also an IP interface for a guest WLAN ( and an IP helper configured (

A Windows DHCP server distributes IP addresses for the Guest WLAN (

As the guest WLAN is managed by an UCOPIA captive portal (which is the gateway for all clients,, I don't have an IP interface for this VLAN on my core router. Because, if I build a, my guests can use this IP address as gateway in their routing table and bypass UCOPIA.


So the question :

My controller IP interface for the guest vlan must have a gateway on the network.

- When I put (the core router, with this interface up), clients obtains an IP address via IP helper from DHCP server. But they can bypass ucopia.

- When I delete IP interface on the core routeur, clients cannot obtain IP address from DHCP server.

I don't know why because the IP helper is which is a server on a directly connected interface on the WLC 5508 (management if)

Is it mandatory to have a valid gateway IP for the controller vlan interfaces ?


Thank you

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Saravanan Lakshmanan Wed, 04/02/2014 - 03:36
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yes, unfortunately it is mandatory to have an valid g.way ip for all interfaces on wlc.

you could try this on test interface and see if it work.

create test interface with g.way ip.

export the config, delete the g.way ip of that interface and restore the edited config. gui may complain about missing g.way ip but the functionality may work.

kaaftab Wed, 04/02/2014 - 21:42
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basically ip helper command forward the protocls DHCP/DNS .etc where required  and  path is provided by the gateway.

abwahid Wed, 09/17/2014 - 08:23
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Yes, it is mandatory to have a valid gateway IP for the controller vlan interfaces.

give a try as saravlak state.


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