Port 25 TCP . SMTP (Outgoing Exchange e-mail)
Port 80 TCP . HTTP (NOT needed normally)
Port 443 TCP . HTTPS (RWW, OWA, remote desktop or Terminal Server sessions)
Port 987 TCP . External secure Companyweb access
Port 1723 TCP . PPTP (VPN)
If port 80 is not open, then you must specify
https:// for RWW connections; otherwise if port 80 is open you can use
http:// and the session will be redirected automatically to port 443. If your router is configured to use UPnP, the Internet Address Management Wizard (IAMW) will open port 80.