Table A: Ports that Enable Remote Access to SBS Services
TCP Port	Service	Description
21	FTP	Enables external and internal file transfer
25	Exchange Server	Enables incoming and outgoing SMTP mail
80 (http://)	IIS	Enables all nonsecure browser access, including: internal access to IIS Webs including the company Web, Windows SharePoint Web, Windows SharePoint administration Web, and server monitoring and usage reports Enables internal access to Exchange by OWA and OMA clients
110	POP3	Enables Exchange to accept incoming POP3 mail
123 (UDP port)	NTP	Enables the system to synchronize time with an external Network Time Protocol (NTP) server
143	IMAP4	Enables Exchange to accept incoming IMAP4-compliant messages
220	IMAP3	Enables Exchange to accept incoming IMAP3-compliant messages
443 (https://)	Outlook	Enables all secure browser access, including external access to Exchange for Outlook 2003, OWA, and OMA clients; required for external access to server monitoring and usage reports
444	Windows Share Point Services	Enables internal and external access to the SharePoint Web
500	IPSec	Enables external VPN connections by using IPSec
1701	L2TP clients	Enables external L2TP VPN connections
1723	PPTP clients	Enables external PPTP VPN connections
3389	Terminal Services	Enables internal and external Terminal Services client connections
4125 (Note: you can change this port in RRAS)	Remote Web Workplace	Enables external OWA access to Exchange, plus internal and external HTTPS access to the client Web site
4500	IPSec	Internet Key Exchange (IKE) Network Address Translation (NAT) traversal