 

       init, mingetty 
login, a login       (. 
""    ).      
 init     mingetty   ,  
  .

    mingetty  
,      login     ,
     login:.  login  
/etc/passwd     .   -
  /etc/shadow  ,      .   ,
login   ;       
.   ,  login   , 
   /etc/shadow.      , login
  Login incorrect (  )   -
   .

    /etc/shadow      -
 MD5 (. ).    .  -
    login     
        /etc/shadow.   
  .

     init   gdm ("GNOME display
manager"    GNOME)     ,
  ,  mingetty  login.  gdm -
 -     .    gdm -
         
/etc/Xll/gdm/PreSession.      ~/.dmrc,  -
      ,    -
.    GNOME  KDE     -
        .

  NIS  login      
  passwd  shadow,       
(   ,  ).      
  (/etc/passwd  NIS),        
/etc/nsswitch.conf (.  "nsswitch.conf:    "
   ).

  (.  ""    )    -
 (Pluggable Authentication Module)     
 ,   /etc/passwd  /etc/shadow.    
   ,    -
   ,      
  . ,       -
         TELNET.   ,  -
,   ,     
(,   -    ).    -

412                                        IV.  