TABLE 1: Exchange Ports for Additional IP Traffic
Protocol	Port	Purpose
HTTP	80	OWA traffic, general-purpose Web traffic
IMAP4	143	IMAP4 (client email protocol with good offline functionality and support for Outlook-like folder structuring) traffic
IMAP4 + SSL	995	SSL-protected IMAP4 traffic
NNTP	119	Public folder and Usenet newsgroup access
POP3	110	POP3 (lightweight client email protocol with limited offline functionality and folder support) traffic
POP3 + SSL	993	SSL-protected POP3 traffic
SMTP	25	Accepts inbound email for further transfer (required for POP3 and IMAP4 clients)