smtp

Simple Mail Transfer Protocol

SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it\'s limited in its ability to queue messages at the receiving end, it\'s usually used with one of two other protocols, POP3 or Internet Message Access Protocol, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving messages that have been received for them at their local server. Most mail programs such as Eudora let you specify both an SMTP server and a POP server. On UNIX-based systems, sendmail is the most widely-used SMTP server for e-mail. A commercial package, Sendmail, includes a POP3 server and also comes in a version for Windows NT. 

Når vi snakker om SMTP taler vi om lag 7 i osi modellen.

Og vi har haft en mindre debat, og vi er blevet enige om at den bruge TCP/IP hvilket er en forbindelses orienteret protocol. Det er den eneste mulighed da den bliver nødt til at oprette en forbindelse hvilket gør den til en forbindelses orienteret protocol

p.s. her kan du læse om SMTPs  features: http://freesoft.org/CIE/RFC/Orig/rfc1869.txt