The nic on the vista machine showed the packets going out, but no reply from the xp machine. DHCP rfc’s 1533, 1534, 1541 and 1542 show that the dhcp ports are 67 and 68. (http://www.comptechdoc.org/independent/networking/guide/netdhcp.html of 6 Aug 2008). Wireshark confirmed vista was using these ports. I then went to xp start/settings/control panel/network connections and looked at local area connection 2 (shared) properties. This is the internet connection sharing nic which has the dhcp server attached. I went to the advanced tab and in the internet connection sharing area clicked settings. Services comes up and showed dhcp (67) and dhcp (68) unchecked. DNS also unchecked.(we had to previously manually insert the dns server entries) I checked them all, a re boot and bingo!

Since I made this change, my xp client pc also sends dhcp requests via ports 67 and 68 so I have no idea how the xp clients would have worked prior to the change.

I hope this helps.
Rob

I hated Vista the moment I laid hands on it. There’s just too much going on in it till it confuses people.

Anyways dude, thanks for sharing your fix. Will surely come in handy

Someone suggested registry clean for fix. I tried that and it worked.
I really don’t like Vista.

Thanks for your help.

Anyways, I’ll ask around for you

After I fixed the issue following your tip, it stppoed working again (showing the same symptom before I tried the tip).
I checked the registry and the Dhcp settings were the same.
I restored them to default and set them again following the tip but it didn’t work.

I wonder if you have any idea.