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beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

DHCP/DNS issue, ever seen this?

So, I have a situation in a building that is quite strange. DHCP server (2008 R2) is set properly to issue the proper addresses. When a wireless client boots, it shows a 192.168.1.1 address in DNS, everything else is correct (IP, domain search, etc.). If you do a renew right away, the problem resolves itself, until the next reboot.

This problem is only happening with wireless clients (Using a Meru Networks controller, set with DHCP relay. It's DNS settings are proper). No rogue DHCP servers are present. I used a few tools, sniffers, and even shut down my DHCP server and tried a few renews, nothing else responded. You can not ping this IP, even setting a static in it's range proved fruitless. I am at my witts end, I don't get it. This is in a windows environment (mostly windows 7 clients), using AD from 2008 R2 as well.

Any ideas appreciated.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.



Minvaren
Premium
join:2001-07-26
Houston, TX

I'd check/tweak the DHCP relay settings on the wireless controller first. Also, look for any address pools defined on it with that subnet in scope - might be getting used as a default somewhere.


H_T_R_N
Premium
join:2011-12-06
Valencia, PA
kudos:1
reply to beachintech

Static set in the alternate configuration settings?



tubbynet
reminds me of the danse russe
Premium,MVM
join:2008-01-16
Chandler, AZ
kudos:1
reply to Minvaren

said by Minvaren:

I'd check/tweak the DHCP relay settings on the wireless controller first. Also, look for any address pools defined on it with that subnet in scope - might be getting used as a default somewhere.

also look for dns redirection in the meru config.
i've not dealt with meru -- but cisco equivalent can masquerade internal network information and set it with the virtual interface information (generally 1.1.1.1). the wlc does all translation on box after the traffic gets there through the capwapp tunnel.

q.
--
"...if I in my north room dance naked, grotesquely before my mirror waving my shirt round my head and singing softly to myself..."


beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to beachintech

said by Minvaren:

I'd check/tweak the DHCP relay settings on the wireless controller first. Also, look for any address pools defined on it with that subnet in scope - might be getting used as a default somewhere.

Best part is this controller doesn't really have any, it's on or off. I hard set the proper DNS settings in the controller (previous was getting it via DHCP), hoping to solve the issue, no joy though.

said by H_T_R_N:

Static set in the alternate configuration settings?

No, this is happening on about 400 machines. I've checked a dozen of them with nothing present. I can take them to a different school running off another control with a similar config with no problems.

said by tubbynet:

also look for dns redirection in the meru config.
i've not dealt with meru -- but cisco equivalent can masquerade internal network information and set it with the virtual interface information (generally 1.1.1.1). the wlc does all translation on box after the traffic gets there through the capwapp tunnel.

q.

I will check again - this system was put in before I started so I am still learning the complete ins and outs and nuances of this system. Cisco is what I am familiar with and this isn't it.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to beachintech

So, I figured out how to make the meru forward all DHCP requests to a specific host rather than pass it through to the internal network untouched. This has resolved the problem as far as I can tell, but I am going to keep searching for the route cause because I have other controllers running in other buildings without this issue.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.