SMTP

SMTP

Simple Mail Transfer Protocol.

SMTP is a protocol for sending (or relaying) e-mail to a server.

SMTP typically uses TCP/IP port 25.

See also: IMAP, POP, MX Record, MSA.

For more information see:

• www.ietf.org/rfc/rfc0821.txt - RFC 821 defines SMTP.
• www.greenend.org.uk/rjk/2000/05/21/smtp-replies.html - SMTP reply codes.
• http://everything.explained.at/Simple_Mail_Transfer_Protocol/ - SMTP explained.