 4.     SMTP, , 14_______________189

R 220 server.esmtp.us SMTP service ready

S EHLO client.edu

R 250-server.esmtp.us says hello

R 250-PIPELINING

R 250-BINARYMIME

R 250 CHUNKING

S MAIL FROM:<one@client.edu> BODY=BINARYMIME

S RCPT TO:<two@server.esmtp.us>

R 250 <one@client.edu>... Sender and BINARYMIME ok

R 250 <two@server.esmtp.us>... Recipient ok

S BDAT 100000

S (First 10000 octets of canonical MIME message data)

S BDAT 324 LAST

S (Remaining 324 octets of canonical MIME message data)

R 250 100000 bytes received

R 250 Message OK, 100324 octets received

S QUIT

R 221 Goodbye

        7- .

 SMTP
   TCP

SMTP     .    TCP
  ,     -
  .  , SMTP-  TCP-
   SMTP   ,  -
  SMTP-    ,  SMTP-
, ,  ,   25.

TCP-   8- .  SMTP
   7- ASCII-,    -
  -  8      0. 8- SMTP-
   .

SMTP-       TCP  -
       TCP/IP.

     SMTP   
 MIME   : RFC-1341, RFC-1342, RFC-1426, RFC-
1521, RFC-1806, RFC-1830, RFC-2045, RFC-2046, RFC-2047, RFC-2048,
RFC-2049, RFC-2076, RFC-788, RFC-821, RFC-822.