Outlook Offline Folders

[Tom]

When clients try to connect to Exchange 5.5 via Outlook
offline folders. They receive a message that the server
is unavailable. This is because some ISP's have blocked
TCP/IP and UDP port 135. Is there any way to change how
the Server and Client communicates?

 

[Lanwench [MVP - Exchange]]

Yes - implement VPN for secure connectivity - and make sure you have a good
firewall protecting your server (all those ports should be blocked - you
just need inbound TCP 25, 80 (for OWA via HTTP) or even better 443 for SSL.
110 if you have external POP users. Etc.

Make sure all remote workers have firewalls, too - either hardware or
software. This is a good wakeup call for you - you shouldn't have had those
ports open in the first place. You have to practice "safe hex."