 continue.    .    -
 ,   .

,    nsswitch.conf    IP-
      DNS.   , -
   DNS, ,    (!) UNAVAIL   .

hosts          dns [!UNAVAIL=return] files

  ,    (return),   DNS 
 UNAVAIL (! UNAVAIL), TO   DNS  SUCCESS, NOTFOUND  TRYAGAIN.
  ,    (files)   , 
DNS- :  DNS-   (   "-
"),       ,     -
.    files (   /etc/hosts)  
  .

 compat:    passwd, group  shadow

  /etc/passwd, /etc/group  /etc/shadow    -
,      compat   nisswitch.conf -
         NIS.

  (+)           NIS;

  (-)  . ,      
passwd    nisswitch.conf  passwd: compat.   -
   passwd  ,      NIS
  ,   +  -.

       passwd     nsswitch.conf
 passwd: compat,      passwd,   -
  NIS,      nsswitch.conf 
passwd: file nis     passwd.



  (   Linux-PAM  Linux Pluggable Authentication Modules
(   Linux))   
,       (. -
)    .    
(.  "  "  27)  (  -
 /lib/security),       
.  ""  ,     
    .  ,   -
 /etc/pam.d,      ,  , -
 .        , -
, /etc/passwd.

        
         .
          -

438                                        IV.  