The following are the most frequently used well known port numbers for email communications or used by mail servers.
Port Number |
Protocol |
Function
|
25 |
TCP |
SMTP Mail Server (for sending outgoing emails) |
110 |
TCP |
POP3 (for receiving email) |
119 |
TCP |
NNTP (Network News Transfer Protocol) |
143 |
TCP |
IMAP4 Protocol (for email service) |
465 |
TCP |
Secure SMTP (email) using SSL |
993 |
TCP |
Secure IMAP protocol over SSL (for emails) |
Gmail Ports
Port |
TCP/UDP |
Service |
995 |
TCP |
Incoming POP3 mail server |
465 |
TCP |
Outgoing SMTP Mail server (SSL Port ) |
587 |
TCP |
Outgoing SMTP Mail Server (TLS/Start TLS Port) |