E-mail-2
Model:
- e-mail are handled at the level of organizations : Cern, IBM, …
- each e-mail for an organization is handled by a relay MTA (Message Transfer Agent)
- MTAs exchanges e-mails between themselves with SMTP
- user accesses e-mail with an UA (User Agent) (e.g. Eudora)
- UA can send e-mails via a local MTA or directly with smtp
- UA can read e-mail in a local spool or via POP (Post Office Protocol) or IMAP (Internet Message Access Protocol)
- SMTP, POP and IMAP use a TCP transport (ports 25,110,143)