I tried to configure Outlook 2003 for POP3 access to my Exchange Server which
is behind an ISA server btw.
I'm able to access on an internal Outlook client with no problems when I
give the mail server setting as a internal ip.

But when I give the mail server setting as the IP address of the external
interface of the ISA server, it stops working.
as in , when i perform Test Settings in Accounts. , the servers are found,
but they do not respond.
I've tried googling this error, but could find no proper resolution

And the funny thing is the same settings work perfectly for Outlook Express.

Hope someone can find the solution.

Thanks in advance