 4.     SMTP, , 14_______________191

     ,   ASCII-, 
   ,     
""  <SP>.     " -
"  " "  <CRLF>.     
 ,        40 .

 -      -,
 ,      -
   <CRLF>.      512 .
 -   :  ("+") 
 ("-ERR").       -
-   ,       
     ,     .

 -      
.       <CRLF>. 
    ,    "."
(  046)  <CRLF>, . .  "CRLF.CRLF".

-    .    TCP-
  -  ,    -
    (AUTHORIZATION state).
    -, . .   -
  .

         
        
(TRANSACTION state).        
   .

      (  QUIT), 
   UPDATE   .   -
 -     (   -
   COMMIT)   TCP-.

   ,    -
, -     .

-        
.     "" ("idle")  
    .    , -
  TCP-,     UPDATE (
,         
ROLLBACK).

(^  ^

 ,  -    , ,
,    , , , -
      . 
 -   "idle"    
    10 .