Installed SP2 on w2k3 server, now users cannot authenticate

Installed SP2 on w2k3 server, now users cannot authenticate.

I hesitated installing sp2 for a long time, once I did, now there are authentication issues….

I turned off the windows firewall, I know, save it, and hte issue went away…

Everything worked fine before and as of now, I have not been able to figure out or I am freaking blind and overlooking something in the firewall settings…

yes this is behind another firewall, the windows firewall is for psuedo redundancy….

I have searched the net for anything relative, but have not found anything that has helped…

Suggestions?