Second Site keeps giving a DHCP Address out randomly to our main sites computers

[twicki]

We have a Windows 2008 Domain with 6 Domian Controllers

2 - Main Site
4 - One Pers other site

We have started having issues that occasionally computers on the main site get the DHCP infornmation from a domain controller on one of the other sites, pull the network cable re-connect and it will get teh correct one.

I have each remote site configured against the relevant subnet and have added each domain controller to the relevant site. Each site is then joined using VPN link (Smoothwall)

I have double checked all the sites and services info and all looks correct, so how is it possible for machine randomaly to pick up the DHCP info from just one of the remote sites????

 

[ShackDaddy]

Sounds like the Smoothwall system is doing DHCP proxy, and is allowing DHCP request broadcasts to cross the VPN link.

Dave Shackelford
ThirdTier.net
TrainSignal.com

 

[twicki]

DHCP is not enabled on the Smoothwall?????

 

[ShackDaddy]

I didn't say DHCP. I said DHCP Proxy. That's an advanced setting that forwards or passes on DHCP broadcasts across a routing connection.

Because of the way DHCP works, it should only provide IPs to clients in the same subnet as the server UNLESS something is forwarding those DHCP-request packages to a different/remote subnet. That's why I'm wondering about your Smoothwall configuration.

Dave Shackelford
ThirdTier.net
TrainSignal.com

 

[twicki]

Apologies, yes I know what you meant but no this is disabled on the smoothwall, and if teh smoothwall was the issue I would expect the addresses to be a variation of the 4 remote networks but instead it is always the same one. Our initial thought was to do with the Panda Antivirus which is cloud based and is installed on all our stations as it installs a network hook driver which is when we forst started noticing the problem, but we have reinstalled the software without the network hook and it is still intemittently happening.