We have recently tried to install ISA 2004 onto our SBS2003 server. The installation is succesful but when we then go to the clients and try to connect, it won't connect to Exchange server. We've tried removing a reinstalling it, clearing the rules, creating custom rules, updating the server but we can't seem to get the clients to connect. But, outside the building we can connect fine as I created an outlook profile on an external PC and VPN'd in fine and could connect to Exchange as normal.
Has anyone had a similar issue or know of a starting point to trouble shoot this issue? The server is mission critical so we can only troubleshoot it out of office hours which is adding to the problem.
Any help is much appreciated,
P.S I tried to add this under ISA zone but it kept saying 'not valid'