Is the DHCP proxy feature of WLC unchecked?  Controller -> Advanced -> DHCP

We had a case where it was enabled (perhaps the default in early versions)
and it never seemed to matter until some years later due to reasons I don't
even remember.  It probably is off, but you might check it.  At the time we
had our problems a TAC engineer said something like "some dhcp servers with
firewalls won't work with this setting".

Just a thought.


On Thu, Aug 21, 2014 at 2:27 PM, Christina Klam <ck...@ias.edu> wrote:

> I am hoping someone can point me in the correct direction.  Two days in
> a row, our wireless controllers (4404 and wism2) have stopped sending
> the DHCP requests for clients for just one of our WLAN.  This WLAN is
> open and is used as the Multicast VLAN for our two 802.1X WLANs.
>
> Recent Changes:
> 1.  Tuesday morning, we replaced our ISC DHCP servers with Infoblox.
> 2.  As part of that change, we had to change the dhcp server settings on
> all of the dynamic interfaces.  In classic mode of Prime, you are not
> allowed to enter just one dhcp address.  So, on the controllers
> themselves, I manually updated the list of dhcp servers  for all of the
> dynamic interfaces except the open one, ias-144.  I was not allowed to
> change the dhcp settings on ias-144 because it was in use.  As we were
> getting near the end of our window, I setup the dhcp override in the
> corresponding WLAN.  (I later remembered it was "in use" as the
> Multicast VLAN.))
> 3.  Wednesday, about 25 hours after the dhcp server change, clients were
> unable to get an ip address.  We "fixed" this issue by disabling the
> WLAN, removing it as the Multicast VLAN, and replacing its dynamic
> interface using a Prime's Lifecycle Theme template.
> 4.  Today at 13:21, the problem reoccurred.  I removed the dhcp override
> option as it was no longer needed.  That didn't help.  We then disabled
> and re-enabled the WLAN.  After doing so, clients were able to get their
> dhcp addresses.
>
>
> Has anyone else seen this behavior?  The ip helper-address is the same
> for all of the WLANs on the 6509 and on the controllers.  All of the
> dynamic interfaces look the same on the controllers.
>
> Thank you for your help,
> --
> Christina Klam
> Network Engineer
> Institute for Advanced Study
> Email:  ck...@ias.edu
>
> Einstein Drive          Telephone: 609-734-8154
> Princeton, NJ 08540     Fax:  609-951-4418
>
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