Finally solved a problem that has been driving me crazy for a while. My eeePC running Vista never seemed to get a DHCP address on either LAN or Wireless when connecting to my Windows Server 2003 box running DHCP. Strangely it had no problem getting a DHCP address from my Optus Wireless Router. I could never work it out what was different. If I set a static IP address on the eeePC it worked fine so it felt as though all the networking was working fine.
Other XP and Vista machines on my network are not having any problem.
I upgraded my eeePC to Windows 7 Release Candidate in an attempt to solve this issue and initially it worked fine. Then one night as I was VPN’d into work the connection died and from then on I couldn’t get a DHCP address and had to start setting static IP addresses again.
Most guidance on the Net seems to point you to this article http://support.microsoft.com/kb/928233 which has to do with Vista’s use of the DHCP Broadcast flag. I actioned the advice in that article but no improvement.
Further hunting around gave a hint to a really handy command: Netsh Winsock Reset Catalog
Running that command and rebooting the machine fixed it straight away. So the problem was an issue with the Winsock stack in the Network stack.
From experience I had an slight inkling of a program that can occasionally corrupt your Winsock stack … the ISA Firewall Client. I run ISA 2006 at home and I usually install the ISA Firewall client on my machines with no problems. I uninstalled and reinstalled the Firewall client and so far no issues.
Netsh Winsock Reset Catalog is your friend.