Hello, I hope I can explain this problem well enough that someone can answer it. I downloaded the Vista image from the technet site and installed it to a machine on my local network. At first everything seemed to be working fine, but then I tried to join the machine to my local Domain Controller to see how that works. Now, the Vista machine will NOT communicate with my DC. After doing some trouble shooting of my own I have found that the Vista machine is getting the DC mac address confused with the default router(gateway) address. Basically it should look like this when I do an arp -a from the command prompt. arp -a (ideally correct config) DNS IP ADDRESS 11.11.11.11 mac address aa-bb-cc-dd-ee-ff-gg Router IP ADRESS11.11.11.12 mac adress 11-22-33-44-55-66 What I am really getting is this DNS IP ADDRESS11.11.11.11 mac adress 11-22-33-44-55-66 Router IP ADRESS11.11.11.12 mac adress 11-22-33-44-55-66 and of course this causes all traffic that the Vista machine is trying to send to my DC to get sent to the router instead. I have tried everything I can think of to get this machine to stop doing this, even installed a different NIC (no I can not confirm if it has valid Vista drivers if anyone can show me where to find them I'll try those too). Any Ideas from one of you guru's out there?

Looks like you have 2 devices with DHCP enabled.

I checked to make sure that the routerdoesnot also have DHCP enabled. The only DHCP server on the network is the domain controller. DHCP is definatly turned off on the firewall/router, but perhaps the problem is still with the firewall/router. It is a Cisco ASA device, if that helps. I have seen comments that there are some conflicts with different routers/firewalls, is this one that vista does not play nicely with? Thanks..