  Powered by DNS

  ¿ nobreak@hongik.com
  3rd Edition,  1999 9 17, Revision 3.2

  ߸   ִٸ ణ ð ҾϿ ڿ ˷ֽñ
  ٶϴ. ̰  鿡 ùٸ  ϴµ ū 
  ˴ϴ.     <http://www.kr.FreeBSD.org/doc/Powered
  ByDNS/>    ,  ȴٸ Ӱ Ȱϼŵ
  ϴ.
  ______________________________________________________________________

  

  1. Domain Name System 
     1.1 DNS Namespace
     1.2   Resolving
     1.3 θ 밡 ڼ (: RFC1035 p7, RFC1032 p2)

  2. Name Server 
     2.1 Name Server 
     2.2 BIND(Berkeley Internet Name Daemon) ġ
     2.3 ۺ (Public Domain) û
     2.4  (Inverse Domain) û
     2.5 Name Server 
        2.5.1 BIND-4 Ʈ  named.boot
        2.5.2 BIND-8 Ʈ  named.conf
        2.5.3 Forward & Reverse Zone ͺ̽
           2.5.3.1 SOA ڵ (Start Of Authority)
           2.5.3.2 NS(Name Server) ڵ
           2.5.3.3 A(Address) & CNAME(Canonical Name) ڵ
           2.5.3.4 MX(Mail eXchanger) ڵ
           2.5.3.5 PTR(Pointer) ڵ
           2.5.3.6 Ÿ ڵ
           2.5.3.7 Zone ͺ̽ Sample
           2.5.3.8 ȣ ü  Zone ͺ̽ Sample
     2.6 Name Server 
     2.7  Ȯ

  3. Ŭ̾Ʈ(Resolver) 
     3.1 Unix ýۿ Ŭ̾Ʈ 
     3.2 Microsoft Windows ýۿ Ŭ̾Ʈ 

  4.   (Domain Parenting & Delegation)
     4.1 θ Zone   
     4.2   
     4.3   in-addr.arpa 
     4.4 Classless in-addr.arpa  (: RFC2317)

  5. DNS Sendmail
     5.1 MX(Mail eXchange) ˰
     5.2 MX ڵ带  ʴ ȣƮ
     5.3 MX CNAME  ( RFC974 p5)
     5.4 Nonrecursive MX lookup
     5.5 Sendmail Virtual Domain 
        5.5.1 m4  sendmail.cf 
        5.5.2 Forward-map ̺ ۼ
        5.5.3 Reverse-map ̺ ۼ
        5.5.4 ̺ ȯ  

  6. BIND /
     6.1 BIND ñ׳
     6.2 BIND Syslog ޽
     6.3 BIND Syslog / ޽
     6.4 BIND Statistics
     6.5 BIND Bebugging Output

  7. DNS   
     7.1 NSLOOKUP
        7.1.1   ˻
        7.1.2 ⺻   
        7.1.3  ó ϱ
        7.1.4 Zone Transfer
        7.1.5 ʱȭ  '.nslookuprc'
     7.2 DIG
     7.3 DNSWALK

  8. Miscellaneous
     8.1 FQDN(Fully Qualified Domain Name)
     8.2 DNS BIND 
     8.3 BIND-4(Traditional) BIND-8(Next Generation) 
     8.4 Public Domain
     8.5 CNAME 뿡 
     8.6 Zone ͺ̽ ۼ 
     8.7 ۷ ڵ (Glue Record)
     8.8 Lame Delegation
     8.9 'Authoritative answer' 'Non-authoritative answer'
     8.10 Positive & Negative Caching
     8.11 Iterative(Nonrecursive) & Recursive Ӽ
     8.12 RTT(Round Trip Time) Nameserver 
     8.13 ϵī ( RFC1034 p25)
     8.14 Serial Number 
     8.15 IP   TTL 
     8.16 ̷    (Load Sharing Between Mirrored Servers)

  9. Bibliography

  ______________________________________________________________________

  1.  Domain Name System 

  Domain Name System̶ ̸ IP ּҸ Ͽִ Ŵ л
  ̹ ý̴. ͳݿ Ǵ IP(Internet Protocol), ׸
  IP  ϴ ݽ   210.105.79.103  
  ǥǴ IP ּҸ νϰ Ǵµ, ̷ IP ּҴ 忡
  ؼϱ  ϱⰡ ư, IP ּҸδ  
  ϱ ٴ  ִ. ͳ   ARPANET 
  IP Address ̸ Ͽ ϰ ϴ  õǾ, 
    DNS Ŀ Ͽ.

  ARPANET  ȣƮ   ʾұ⿡ NIC(Network Information
  Center)κ  ֱ⸶ ȣƮ  (HOSTS.TXT) ޾
  /etc/hosts Ͽ Ͽ. ׷  ͳ Ը ȣƮ
   Կ  ο ̸  ü ʿ伺 εǾ, 1983
  Paul Mockapetris RFC882, RFC883( RFC1034 ü) ο
   ü    ǥϸ, ũ ӽ̽  ,
  л ͺ̽, Email   ־ DNS źϿ.

  1.1.  DNS Namespace

  ARPANET ߾  ü ϳ Ϸ  ȣƮ
  Ͽ, DNS ̰    Ʈȭ Ͽ [׸ 1]
   · Ѵ.

       [Image]
       [׸ 1] Namespace 

  丮     ִµ, Root domain(Ʈ ǥõǴ)
  Top level ο  , Top level    ο
    /ϴ  Ѵ. ̷  
  Ͽ    Ӽ(NS:Name Server) л, ȴ.

   YAHOO.COM  COM Ӽ ϵǾ ְ, WWW.YAHOO.COM
  YAHOO.COM Ӽ , ȴ.  AV.YAHOO.COM ϱ
  ؼ YAHOO.COM  ϴ Ӽ  ڵ常
  ν ϴ. ̷ ӱ ϴ ͳ ȣƮ 
   ȿ ϰ ش.
  1.2.    Resolving

       [Image]
       [׸ 2]  'WWW.YAHOO.COM'  IP Resolving

    TCP/IP Ŷ θ   . 
  θ  IP ȯ۾(Resolving) ϰ Ǵµ, [׸ 2]
  ̷ Resolving  ش.

  1. Client  'WWW.YAHOO.COM' ϱ  ڽ Local Name
     Server(TCP/IP  ) Ѵ.

  2. Local NS  ڽ ĳ ڷᰡ ִ Ȯ  ߰ߵ
      Root NS(Root NS  ִ) Ǹ .  ׷
     Root NS 'WWW.YAHOO.COM' ڷḦ   Ƿ, COM 
     ϴ NS ϶ 亯 ش.

  3. Local NS ٽ COM NS Ǹ , COM NS ٽ YAHOO.COM
     NS Ϸش. (Ʈ(Ʈ) COM  Root NS  Ǳ
         Ͼ ʰ (2) ٷ YAHOO.COM NS
     ϶ 亯 ´.)

  4. Local NS YAHOO.COM NS Ѵ. YAHOO.COM NS 굵ο
      ڷḦ ϴ  NS ̹Ƿ, answer) Ѵ. (
     'WWW.YAHOO.COM'  IP resolving ϸ Ź ٸ IP ּҰ
     Ѿ    ִµ, ̴ Ʈ ټ ̷ 
     ǰ,    ش ο ټ IP Ͽ
     ̴. (: "̷   ")

  5. , Local NS Client  Ѵ.

  1.3.  θ 밡 ڼ (: RFC1035 p7, RFC1032 p2)

  ڳ ڷ Ͽ ϸ,  ڿ  ȴ. (ʱ
  [RFC1035] θ ݵ ڷ ϵ Ͽ,
  [RFC1123 p12] ȭǾ 3com.com    Ǿ.)
    /ڿ   , Ʈ иǴ  ڿ(Each
  segment) ְ 63 ܾ(octet)   ֵ Ǿ
  (NIC 12ܾ Ϸ ϱ⸦ ), /ҹڴ е
  ʴ´.

  ٿ, θ ϱ(KRNIC, INTERNIC ) , ݾ 
  Ģ  . KRNIC ڷ ϴ θ 
  ʴ ݸ ׸Ʈ 63ڱ Ǯ, INTERNIC ڷ
  ϴ  ǰ, ׸Ʈ 22ڷ Ѵ.

   θ  Email ǹǷ RFC822 Ģ
  ؼؾ  ʿ䰡  ˾ƾ Ѵ. , ̴  ο
   Ģ ϹǷ, ũ Ű澵 ʿ ڴ.

  (۵Ǵ Ʈ ǥ ԰ݺ Ȯǰ ϰ Ǿ
   ڷθ  (:411.com) Ѵ.  ǥؿ Ǵ
    뿡 Ǹ   ٴ ̱⵵ ϴ)

  2.  Name Server 

  2.1.  Name Server 

  Ӽ Primary, Secondary, Cache only server еȴ.

  Primary server ش  ϴ  Ӽ̰, Secondary
  server Ư ο  back-up copy ϴ ̴.
  Secondary Primary    ϸ лŰ 
  ϸ, ټ   ִ.   ϱ ؼ
  Primary, Secondary  ʿϰ Ǹ, Secondary Ģ ܺ
  Ʈ ġ   · Primary ٿǾ  Ѵ.
  ,  ϱ ؼ ּ 2(Primary * 1, Secondary *
  n) ̻ Ӽ 䱸ȴ.(δ Primary ε 
  ϰ, Resolver 忡 Primary Secondary е
  ʴ´.)

  Cache only server ο  ͸  ʰ,
  resolving ó ش. ,  簡 ְ  ȸ Primary,
  Secondary Name server  翡 ġѴٰ  , 翡 ġ
  Ʈũ  Local DNS server  ȴ. ̷  
  resolving 䱸  ٸ Ʈũ()  õϰ ǹǷ
  ణ ̰  Ǹ,  Ʈũ  Ǿ 絵
   ͳ  Ұ  ִ. ̷  翡 Cache
  only server ϸ ȿ  ذ  ִ.

  2.2.  BIND(Berkeley Internet Name Daemon) ġ

  Name server ϱ ؼ   α׷ ʿϰ
  Ǵµ,  BIND db   ս ǥ   
  μ ͳݿ  θ ȴ. κ Unix ýۿ
  BIND ̹ ġǾ ִ. /usr/sbin 丮 in.named Ȥ named
   Ȯϰ, BIND ̹ ġǾ  쿡  
  ġ BIND  ȮѴ. (BIND ̿ )

       $ dig @ns.nobreak.com txt chaos version.bind. | grep VERSION
       VERSION.BIND.           0S CHAOS TXT    "8.2"

  <http://www.isc.org/bind.html> BIND ֽŹ Ȯϰ,
  ̰ ų   ɰ  Ǿٸ, ׷̵带
  ϰ, BIND-4 ġǾ ִٸ, BIND-8 ̱׷̼Ͽ ο
  帧 ϴ°͵  ʰڴ.

  BIND ġ ſ ϴ.  <ftp://ftp.isc.org/isc/bind/src/>
  ֽ  ҽ ޾,  Ǭ    Էϴ
   ġ ʿ ̴.

       # make clean depend all install

  ׸, ý rc ũƮ  Ͽ ý ý BIND
  ڵ   ֵ Ѵ. (FreeBSD: /etc/rc.conf,
  /etc/rc.network | Solaris: /etc/init.d/inetsvc | Linux
  /etc/rc.d/init.d/named)

  Windows NT, OS/2, MacOS  BIND ϰ Ѵٸ,  
  .

  o  <http://www.dns.net/dnsrd/docs/exotic.html>

  o  <http://www.isc.org/bind.html>

  2.3.  ۺ (Public Domain) û

  Primary, Secondary Ӽ غǾ, û 
  Ǿٸ,    (``YourDomain.COM'' Internic,
  YourDomain.CO.KR Krnic)  ûϿ ߱(ӽ̽
  ũ) ް ȴ.  û  ݾ 
  Ϲ , å, ,  , Ӽ 
  䱸ȴ.  û  ӽ̽ ũϱ  Ӽ
     ۼѴ.

       2.   Complete Domain Name.......: NOBREAK.COM
       7a.  Primary Server Hostname....: NS.NOBREAK.COM
       7b.  Primary Server Netaddress..: 210.105.79.2
       8a.  Secondary Server Hostname..: NS2.NOBREAK.COM
       8b.  Secondary Server Netaddress: 210.105.79.3

  ``NOBREAK.COM'' ϵǾٴ ޽ ޾Ҵٸ,   ش
    θ ȮѴ.

       $ nslookup -type=ns nobreak.com
       Server:  ns.nobreak.com
       Address:  0.0.0.0

       nobreak.com     nameserver = ns.nobreak.com
       nobreak.com     nameserver = ns2.nobreak.com
       ns.nobreak.com  internet address = 210.105.79.2
       ns2.nobreak.com internet address = 210.105.79.3

  ش ο  Ӽ û Ͱ  ǥõȴٸ, 
  ٸ  ̴.   ȵǾٸ,   ޽ 
   ִ.

       *** local.name.server can't find nobreak.com.: Non-existent host/domain

  " NOBREAK.COM ûϴµ   Ϻο ִ NS.NOBREAK.COM,
  NS2.NOBREAK.COM Ҽ ֽϱ?"  "NS.NOBREAK.COM NOBREAK.COM
   û Ϸ  Ӽ  ־   
  ʽϱ?" ǹ   ִµ,    
  ϱ  Ӽ   ο Ǳ 
  ϴ. (: ``۷ ڵ'')

  2.4.   (Inverse Domain) û

  ι  IP  ش   ã  ֵ ϴ
  ̴.  ISP(Internet Service Provider) IP Ҵ 
   ûѴ.   ι ο  Ӽ in-
  addr.arpa ӽ̽ ϵǾ ִ ȮѴ.

       $ nslookup -type=ns 79.105.210.in-addr.arpa (C Class 210.105.79.x Ҵ ޾ )
       Server:  ns.nobreak.com
       Address:  0.0.0.0

       79.105.210.in-addr.arpa nameserver = ns.nobreak.com
       79.105.210.in-addr.arpa nameserver = ns2.nobreak.com
       ns.nobreak.com  internet address = 210.105.79.2
       ns2.nobreak.com internet address = 210.105.79.3

     ޽ ´ٸ, ι   ȵǾ ִ
  ̹Ƿ, ش ISP ûϿ Ѵ.

       *** ns.nobreak.com can't find 79.105.210.in-addr.arpa.: Non-existent host/domain

  2.5.  Name Server 

  [׸ 3] 'NOBREAK.COM' ο   Ʈũ  ̴.

       [Image]
       [׸ 3] Ʈũ 

  Ʈũ  3 Ǿ ִ. DNS ϱ , ׸ 
  ̸   ȣƮ IP ο.  Ӽ ns(primary),
  ns2(secondary) ȣƮ ϰ, IP 1( ޾ 쿣
  129)  Ȥ ġ, 2 NS, 3 NS2 ҴѴ. 
  NOBREAK.COM ռ Internic ûϿ, NS.NOBREAK.COM,
  NS2.NOBREAK.COM Ӽ  ϸ ȴ.

  2.5.1.  BIND-4 Ʈ  named.boot

  BIND-4 Ʈ  named.boot BIND õ Ǹ,   ʿ
  ϴ ȯ  ο  Primary/Secondary 
  ȴ. Ϲ ý /etc/named.boot ġϸ, κ
  н ŸƮ ũƮ Ʈ  ϸ õ BIND ڵ
  Ѵ. Ʈ ϻ  Ʈ ݵ 1  Ͽ ϸ
  ';' ּ ǹѴ.
       directory  /var/named

  δ Ʈ Ͽ Ÿ ϵ ̽ η ۿѴ. 
  ϵ  θ   ǥؾ ϸ ⼭ /var/named
  丮 ̽ 丮 Ѵ. (κ ý ⺻ ̽ δ
  /var/named, /etc/named Ȥ /etc/namedb ̴.)

       cache  . named.root

  cache ڵ  ״ ĳ ƴ϶ Ʈ Ӽ  ִ
  ͺ̽  Ÿ. BIND Ÿ   Ʈ
  Ӽ ϴµ,  Ʈ Ӽ   
  Ͽ ϰ ȴ. '/var/named/named.root'  ̽
  丮 ġŰ ȴ.

  ĳ  Internic ϸ,
  <ftp://ftp.rs.internic.net/domain/named.root>   ִ.  Ʈ
  Ӽ     ݾ ٲ ,  ޿
  ѹ Ʈ  ʿ䰡 ִ. ũƮ Cron 
   ĳ  Ʈϴ ͵  ̴.

       primary  nobreak.com  zone-nobreak.com

  ش ο  Primary Ӽ  Ѵ. 
  nobreak.com ο    Primary ̸, ͺ̽ 
  /var/named/zone-nobreak.com  Ÿ.

       secondary  nobreak.com  210.105.79.2  sec-nobreak.com

  ο  Secondary Ӽ Ѵ.  ° ʵ Primary
  Ӽ IP ּ̰,  ° ʵ Primary   zone
    ϸ̴. 210.105.79.2κ nobreak.com 
  ͺ̽ (Zone Transfer)޾ /var/named/sec-nobreak.com
   Ѵ.

  [׸ 3] Ʈũ  Ʈ    ۼ  ִ.

        NS.NOBREAK.COM(Primary NS) /etc/named.boot 
       directory                           /var/named
       cache      .                        named.root
       primary    0.0.127.in-addr.arpa     zone-0.0.127.in-addr.arpa    ; loopback
       primary    79.105.210.in-addr.arpa  zone-79.105.210.in-addr.arpa ; Reverse ZONE
       primary    nobreak.com              zone-nobreak.com             ; Forward ZONE

  loopback ּҰ  ʴ ý  , 'primary
  0.0.127.in-addr.arpa ...'   Ӽ  ִ. 
     Ҵ C Class IP  210.105.79 

        NS2.NOBREAK.COM(Secondary NS) /etc/named.boot 
       directory                           /var/named
       cache      .                        named.root
       primary    0.0.127.in-addr.arpa     zone-0.0.127.in-addr.arpa
       secondary  79.105.210.in-addr.arpa  210.105.79.2  sec-79.105.210.in-addr.arpa
       secondary  nobreak.com              210.105.79.2  sec-nobreak.com

  Secondary Ӽ ̴. loopback Primary Ƶд.
  Secondary  ̰ ̴.  (/var/named/zone-0.0.127.in-
  addr.arpa ־ )

  Secondary ش  Primary Ͽ  ̽ ۹޾,
  sec-79.105.210.in-addr.arpa, sec-nobreak.com , Ѵ.

  2.5.2.  BIND-8 Ʈ  named.conf

  BIND-4 BIND-8   ۼ ϰ ̰  κ ٷ
   Ʈ ̴. BIND-8 Ʈ  ⺻  BIND-4
  ,  κ ߰ ȮǾ , ̸ ϰ 
  ߰ ս   ֵ   Ǿ.  ׸
   Ʈ ϰ ȥ  named.conf  Ǿ.
    C   ſ     ִ.   
  ϰ   ֵ ۼ ٲ , BIND-4 Ʈ ϰ ũ
  ٸ  .  ռ ۼ BIND-4  Ʈ  BIND-8
  ° ȯ ̴. Ϲ BIND-8  Ʈ   
  ڵ Ȱ, ̳ κ Ƿ   ˰
  ʹٸ <http://www.isc.org/bind8/config.html> ϱ ٶ.

   Primary Ӽ  Ʈ ̴.

   NS.NOBREAK.COM(Primary NS) /etc/named.conf 
  // ̰ ̴ּ. BIND-8 ';' ּ ƴ϶,   ǹѴ.
  options {
          directory "/var/named";             // Zone  ̽ 丮
          dump-file "/var/tmp/named_dump.db"; // Dump  Ǵ 
          statistics-file "/var/tmp/named.stats"; //   Ǵ 
          pid-file  "/var/run/named.pid";     // μ ID    
  };
  logging {   // ʿ  αϿ  ʴ´.
          category lame-servers { null; };
          category cname { null; };
          category response-checks { null; };
          category notify { null; };
  };

  zone "." IN {                       // ĳ 
          type hint;
          file "named.root";
  };
  zone "0.0.127.in-addr.arpa" IN {    // localhost  Primary  
          type master;
          file "zone-0.0.127.in-addr.arpa";
  };
  zone "79.105.210.in-addr.arpa" IN { // Ҵ IP   Reverse Zone
          type master;
          file "zone-79.105.210.in-addr.arpa";
  };
  zone "nobreak.com" IN {             //  'NOBREAK.COM'  Forward Zone
          type master;
          file "zone-nobreak.com";
  };

  Secondary Ӽ  Ʈ    ۼȴ.

   NS2.NOBREAK.COM(Secondary NS) /etc/named.conf 
  options {
          directory "/var/named";
  };
  logging {
          category lame-servers { null; };
          category cname { null; };
  };

  zone "." IN {
          type hint;
          file "named.root";
  };
  zone "0.0.127.in-addr.arpa" IN {    // localhost  Primary  
          type master;
          file "zone-0.0.127.in-addr.arpa";
  };
  zone "79.105.210.in-addr.arpa" IN { // Reverse Zone Secondary 
          type slave;
          file "sec-79.105.210.in-addr.arpa";
          masters { 210.105.79.2; };  // Primary NS IP ּ
  };
  zone "nobreak.com" IN {             // 'NOBREAK.COM' Secondary 
          type slave;
          file "sec-nobreak.com";
          masters { 210.105.79.2; };
  };

  2.5.3.  Forward & Reverse Zone ͺ̽

  Zone  Forward, Reverse   еȴ. Forward Zone
  ο  IP   ִ ͺ̰̽, Reverse Zone
  IP    ͺ̴̽. ռ named.boot Ͽ
  Ӽ loopback, 79.105.210.in-addr.arpa, nobreak.com ο
   Primary ϵ Ͽ.  zone-0.0.127.in-addr.arpa
  zone-79.105.210.in-addr.arpa Reverse Zone ̰, zone-
  nobreak.com Forward Zone ̴. Zone  BIND-4 BIND-8
  ۼ ϴ.

   [׸ 3] Ʈũ   Forward Zone  zone-
  nobreak.com ۼϿ .

  2.5.3.1.  SOA ڵ (Start Of Authority)

  Zone  ׻ SOA ڵ Ѵ. SOA ڵ ش ,
  nobreak.com  Ӽ (authoritative) ڷḦ  
  ǹϸ, ڷᰡ  · ,   ֵ Ѵ.

       nobreak.com. IN  SOA  ns.nobreak.com. hostmaster.nobreak.com. (
                             1998122800  ;Serial
                             21600       ;Refresh ( 6 hours)
                             1800        ;Retry   (30 minutes)
                             1209600     ;Expire  (14 days)
                             86400)      ;Minimum ( 1 day)

  1 ش Zone Ͽ  θ . θ 
  Ʈ  .   θ  '@' ǥø Ͽ
  ȴ.

       @            IN  SOA  ns.nobreak.com. hostmaster.nobreak.com. (

  IN(Internet) Ŭ̴. HS, HESIOD, CHAOS  Ŭ
  , Ϲ  Ƿ ׻ IN ȴٰ
  .

  SOA  Primary Ӽ  Email ּҰ .
  Ʈ(Responsible Person)μ ο  ߻  ̸
  ϴ 뵵 ȴ. Namespace    ϴ
  'lamers'    Ǿ   Email Ͽ
  ش.

   ȣ ѷ κп Serial, Refresh, Retry, Expire, Minimum
  5 ð() ʵ尡 δ. Minimum  4 ʵ Secondary
  Ӽ ϱ  ̴. ⺻  ''̰, ȣ
  M(Minute), H(Hour), D(Day), W(Week) ٿ 30M, 8H, 2D, 1W 
    ִ.

  o  Serial: Serial Secondary Zone  θ   ֵ
     ϱ ̴. Secondary  Serial Primary Serial
       Zone   ޴´.  Zone   
     Serial  ʴ´ٸ, Secondary īǸ Ʈ
      . Secondary ٸ Serial ǹ̰  ׷
      Zone  Ǿ  Serial ϴ  
     ̴.

  o  Serial ǥ ϴ  ں Ϲ  
     YYYYMMDDNN  ǥѴ. YYYYMMDDNN  ǥ 4294
     ǥ ϴ.

  o  Refresh: Primary Zone ͺ̽ θ Secondary
     ˻ϴ ̴ֱ. Ʈũ   Zone 
     ȴٸ, 3H(10800)  Ѵ. Zone Ǵ 
     Ϲ 6H(21600) - 12H Ѵ.

  o  Retry: Secondary, Primary  ȵ ,  õ ð
     ̴ֱ. Refresh Ⱓ   ǹ̰ , κ 
     30M(1800) - 1H Ѵ.

  o  Expire: Secondary Expire  ð Primary 
      ,  ī ڷᰡ  ̻ ȿ ʴٰ ,
     ش ο  亯  ʴ´.   ʹ  åϴ
       ʴ.  1W - 2W(1209600) Ѵ.

  o  Minimum: Ÿ Ӽ  Zone  ڷḦ   , 
     ڷῡ  ȿⰣ(ĳ ִ ð) Ѵ.  TTL(Time To
     Live) õ  ڵ   ⺻  ȴ. Ư
     ڵ尡 Ǿ , ̰ ͳݿ ĵǾ ƮǴ
     ֱ   Minimum  Ѵ. Ϲ SOA
     1D(86400) Ͽ ü ڵ忡 ϰ,   Ǵ
     ڵ常  1H - 3H  ߴ  Ѵ. 0
     ĳ   ǹ̴.

  2.5.3.2.  NS(Name Server) ڵ

  NS ڵ ش ο  Ӽ   Ÿ.

       nobreak.com.   IN  NS      ns.nobreak.com.
                      IN  NS      ns2.nobreak.com.

   ٸ NS Ȱδ, Ŵ ο   ٸ Ӽ
  Ҷ ̴. Namespace   NS ڵ ̷ µ,
  Ŵ   شϴ κ̹Ƿ, ⼭ ش ο 
    Ÿٰ ˾Ƶ. " " ڼ ٷ.

  2.5.3.3.  A(Address) & CNAME(Canonical Name) ڵ

  A ڵ ο IP οѴ.   . mail power A
  ڵ IP  Ͽ. (mail 'mail.nobreak.com.' ϰ
  ؼȴ.)

       ; Host addresses
       mail.nobreak.com.   IN  A      210.105.79.2
       power               IN  A      210.105.79.103
       ; Aliases
       www                 IN  CNAME  power.nobreak.com.
       ftp                 IN  CNAME  www

  CNAME ڵ ο   ٸ ̸ ϵ Ѵ.  
  power.nobreak.com, www.nobreak.com, ftp.nobreak.com   IP
  210.105.79.103  ȴ. ftp  CNAME CNAME  ϴ
  ,  DNS  ڷῡ ٸ ǰ , ̰
  ϴ. CNAME ϴ   ڵ带  ӹޱ
  , CNAME   ߰ ڵ带   
  Ѵ. , MX, NS  ڵ忡 CNAME  
  ־ ȵȴ. ݵ Ͽ Ѵ. CNAME ߸  BIND
  α׸    ã Ƿ, Ȯ   ٸ
  CNAME  ڵ带 ƿ ٸ ڵ ڷ  ʴ 
  . õ  ޴ ߿ ƮȰ, ս 鿡
  CNAME   ʴ 쵵 ִ.  (: ``CNAME 뿡
  '')

       ftp                 IN  CNAME  www  ; (X) CNAME ߰ڵ带  
                           IN  MX     mail ;     .

       power               IN  MX 10  mail ; (X) MX CNAME 
       mail                IN  CNAME  ns   ;     ڵ尡   .

  2.5.3.4.  MX(Mail eXchanger) ڵ

  MX ڵ ش ȣƮ   θ Ѵ.  
  Ǿ  , account@nobreak.com     
  'mail.nobreak.com.'  ۵ȴ.  'mail.nobreak.com.' 
   ٸ,  켱 'power.nobreak.com'  ϰ
  ȴ. MX Priority_Number   ϸ, Priority_Number ڴ
   켱 . "MX(Mail eXchange) ˰" ڼ
  ٷ.

       nobreak.com.        IN  MX  10  mail.nobreak.com.
                           IN  MX  20  power.nobreak.com.
       mail.nobreak.com.   IN  A       210.105.79.2
       power.nobreak.com.  IN  A       210.105.79.103

    MX ڵ忡 CNAME    ȵȴ.  ̷
    MTA(Mail Transfer Agent: sendmail)   θ ã
  Ͽ,  ְ  . ̴ ۽ ϴ MTA 
   ̹Ƿ,    ޴ ƴϸ  
  ϱ⵵ ƴ. ݵ .

       nobreak.com.        IN  MX  10  mail.nobreak.com.  ; (X) ߸ 
       mail.nobreak.com.   IN  CNAME   power.nobreak.com.
       power.nobreak.com.  IN  A       210.105.79.103

  2.5.3.5.  PTR(Pointer) ڵ

  PTR ڵ IP ּҿ  θ Ͽ ָ, Reverse Zone
  Ͽ ȴ.  IP 210.105.79.2   ̴.

       2.79.105.210.in-addr.arpa.  IN  PTR  ns.nobreak.com.

  Forward Zone ټ  A(Ȥ CNAME) ڵ带  
  IP   , PTR ڵ ߺ  ʱ , ش
  IP  ǥ θ ϳ Ͽ Ѵ.

  2.5.3.6.  Ÿ ڵ

  Zone ͺ̽ ʿ ڵ   ͸ε
  ,   ڵ Ѵ.  ݵ ʿ
  ,  Ǵ ڵ带 ҰѴ.  ڼ  ʿϴٸ
  RFC1035, RFC1183, RFC2163 .

  power           IN  A      210.105.79.103
                  IN  HINFO  "Sun Sparc Ultra 5"  "Solaris 2.6"
                  IN  TXT    "Nobreak's Primary Server"
                  IN  TXT    "WWW, FTP is now available"
                  IN  RP     hostmaster.nobreak.com.  hostinfo.nobreak.com.
  hostinfo        IN  TXT    "Seung-young Kim, +82-42-864-4440/1"

  HINFO(Host INFOrmation) ڵ   ڿ(CPU , OS )
   ý  Ÿ. ڿ  ԵǾ  쿡
  ݵ ūǥ Ͽ Ѵ.

  TXT(TeXT) ڵ ؽƮ   øǾ   ִ.
  RP(Responsible Person)   ǥϴµ, Email ּ(@
  Ʈ ġȯ),  (TXT ڵ带   )
  ´. HINFO   ڵ   ġ ƾ
  Ѵٴ ǰߵ ִ.

  2.5.3.7.  Zone ͺ̽ Sample

  [׸ 3] Ʈũ   Forward Zone  zone-nobreak.com
    ۼ  ִ.

        'NOBREAK.COM' ο  Forward Zone  /var/named/zone-nobreak.com

       @               IN      SOA     ns.nobreak.com. hostmaster.nobreak.com. (
                                       1998122801  ;Serial
                                       21600       ;Refresh ( 6 hours)
                                       1800        ;Retry   (30 minutes)
                                       1209600     ;Expire  (14 days)
                                       86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nobreak.com.
                       IN      NS      ns2.nobreak.com.
                       IN      MX 10   mail           ;   ȣƮ

       mail            IN      A       210.105.79.2

       ; Hosts Here - This is comments
       router          IN      A       210.105.79.1
       ns              IN      A       210.105.79.2
       ns2             IN      A       210.105.79.3
       power           IN      A       210.105.79.103
                       IN      HINFO   "Sun Sparc Ultra 5"         "Solaris 2.6"
                       IN      TXT     "Nobreak Technologies, Inc."
       www             IN      CNAME   power

  ι   Reverse Zone  zone-79.105.210.in-addr.arpa
    ۼȴ.

   Reverse Zone  /var/named/zone-79.105.210.in-addr.arpa

  @               IN      SOA     ns.nobreak.com. hostmaster.nobreak.com. (
                                  1998122801  ;Serial
                                  21600       ;Refresh ( 6 hours)
                                  1800        ;Retry   (30 minutes)
                                  1209600     ;Expire  (14 days)
                                  86400)      ;Minimum ( 1 day)
                  IN      NS      ns.nobreak.com.
                  IN      NS      ns2.nobreak.com.
  ; IP-Domain mapping here
  1               IN      PTR     router.nobreak.com.
  2               IN      PTR     ns.nobreak.com.
  3               IN      PTR     ns2.nobreak.com.
  103             IN      PTR     power.nobreak.com.

  loopback ּҸ  Reverse Zone     ۼȴ.  IP
  127.0.0.1 'localhost.' ϴ  ̹Ƿ,   
  Ʈũ ϰ ۼ ̴.

        loopback  Reverse Zone  /var/named/zone-0.0.127.in-addr.arpa

       @               IN      SOA     ns.nobreak.com. hostmaster.nobreak.com. (
                                       1998122801  ;Serial
                                       21600       ;Refresh ( 6 hours)
                                       1800        ;Retry   (30 minutes)
                                       1209600     ;Expire  (14 days)
                                       86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nobreak.com.
                       IN      NS      ns2.nobreak.com.
       ; IP-Domain mapping here
       1               IN      PTR     localhost.

  Zone Ͽ  ǥ ݵ FQDN ǥ  Ѵ.
  BIND Ʈ  ʴ ڿ ȣƮ óϹǷ, 
  'ns.nobreak.com.'  Ʈ  FQDN ǥϰų, 
  ߻ϹǷ, .

  2.5.3.8.  ȣ ü  Zone ͺ̽ Sample

  ȣþü    ټ  ϳ Zone
  ͺ̽   ִ. , ȣ κ  Zone
  Ѵٸ, ȣ  IP ȭ  õ  Zone Ǿ
  ϴ Ȳ  ʱ⸦ ⵵ϰų, ݳ  Ҽ ִ
  ⸦  ̴. ⼭ Ұϴ  ڰ  ȣ
  üϼ ϰ Ȱ  ,  ߰// 
  ð     ̴.

  * named.boot (BIND-4)
  primary         netbsd.org                      zone-default
  primary         openbsd.org                     zone-default
  ...
  primary         freebsd.org                     zone-freebsd.org     ;  ߰  ʿ 
  ...

  * named.conf (BIND-8)
  zone "netbsd.org"       IN { type master; file "zone-default"; };
  zone "openbsd.org"      IN { type master; file "zone-default"; };
  ...
  zone "freebsd.org"      IN { type master; file "zone-freebsd.org"; };
  ...

  * zone-default
  @               IN      SOA     ns.nobreak.com. hostmaster.nobreak.com. (
                                  1999030601  ;serial
                                  21600       ;Refresh ( 6 hours)
                                  1800        ;Retry   (30 minutes)
                                  1209600     ;Expire  (14 days)
                                  86400)      ;Minimum ( 1 day)
                  IN      NS      ns.nobreak.com.
                  IN      NS      ns2.nobreak.com.
                  IN      A       210.105.79.39
                  IN      MX 10   @
                  IN      MX 20   mqueue.nobreak.com.

  www             IN      CNAME   @
  telnet          IN      CNAME   @
  ftp             IN      CNAME   @
  mail            IN      CNAME   @
  pop             IN      CNAME   @
  news            IN      CNAME   news.nobreak.com.

  * zone-freebsd.org
  $INCLUDE zone-default

  ftp.kr          IN      A       147.46.102.39
  www.kr          IN      CNAME   @

  2.6.  Name Server 

  Ӽ ϱ   Ǿ.  ϵ
  غǾ Ȯ , Ӽ . Ϸ  
  .

   NS.NOBREAK.COM (BIND-8)
  # ls /etc/named.conf     # BIND-8 Ʈ 
  /etc/named.conf
  # ls /var/named/         # Zone ͺ̽  Ȯ
  named.root
  zone-0.0.127.in-addr.arpa
  zone-79.105.210.in-addr.arpa
  zone-nobreak.com
  # /usr/sbin/named        #    (Solaris: /usr/sbin/in.named)
  # ps ax | grep named     # μ  Ȯ (Solaris: ps -e | grep in.named)
    254  ?  S    0:00 named

   NS2.NOBREAK.COM (BIND-4)
  # ls /etc/named.boot      # BIND-4 Ʈ 
  /etc/named.boot
  # ls /var/named/          # Zone ͺ̽  Ȯ
  named.root
  zone-0.0.127.in-addr.arpa
  # ndc start               # ndc(Name Daemon Control) ġǾ  
  Name Server Started
  # ndc status
    254  ?  S    0:00 named
  # ls /var/named/          # Primary Zone ۿ Ȯ
  named.root
  sec-79.105.210.in-addr.arpa
  sec-nobreak.com
  zone-0.0.127.in-addr.arpa

  2.7.   Ȯ

  ⿡ [׸ 3]  Ʈũ    ٷ,
  ⺻ ʿ κ  Ǿ Ƿ  Ʈũ 
     ϸ ȴ.   Ÿ Ӽ 
  Ǹ ν, Namespace   Ǿ  Ȯ.

       $ nslookup power.nobreak.com ns.nobreak.com   # Primary  Ȯ
       Server:  ns.nobreak.com
       Address:  0.0.0.0

       Name:    power.nobreak.com
       Address:  210.105.79.103

       $ nslookup power.nobreak.com ns2.nobreak.com  # Secondary  Ȯ
       Server:  ns2.nobreak.com
       Address:  210.105.79.3

       Name:    power.nobreak.com
       Address:  210.105.79.103

       $ nslookup power.nobreak.com ns.kornet.ne.kr  # Namespace ũ Ȯ
       Server:  ns.kornet.nm.kr
       Address:  168.126.63.1

       Name:    power.nobreak.com
       Address:  210.105.79.103

   3 ǰ  Ǿٸ, ϴ Ӽ 
  ȴٰ ص . Ȯ ϱ ؼ, α м 
  Zone ͺ̽   BIND  ¸ 캸ƾ Ѵ.

  3.  Ŭ̾Ʈ(Resolver) 

  3.1.  Unix ýۿ Ŭ̾Ʈ 

  Unix ýۻ󿡼 DNS ϱ ؼ /etc/resolv.conf ϰ,
  /etc/nsswitch.conf  պƾ Ѵ. /etc/resolv.conf 
  Resolving   Ӽ 3   ִ.  Ϲ
   Primary, Secondary, ISP Ӽ 3   Ѵ.

       search nobreak.com       #  Ƚ(Suffix)
       nameserver 210.105.79.2  # ns.nobreak.com
       nameserver 210.105.79.3  # ns2.nobreak.com
       nameserver 168.126.63.1  # ns.kornet.ne.kr (ϴ ISP NS)

   Ѵ. ٸ  ȣƮ  ϰų,  
  Ѵٸ, ش       ִ.

       search nobreak.com kr.freebsd.org

  ̷ 쿣 ȣƮ www  www.nobreak.com ȮǾ ˻ǰ,
  ˻   www.kr.freebsd.org ȮǾ ٽ ˻ȴ. ߸
  ȣƮ ־,    ˻ϹǷ,  
  search Ʈ ϴ  ٶ ʴ.

       Ӽ ٸ   ִ.
  ַ Ӽ ĳ   ʰ, ش   ﰢ
  ϱ  δ.

       search nobreak.com

       domain nobreak.com
       nameserver 210.105.79.2
       ...

       domain kornet.ne.kr
       nameserver 168.126.63.1
       ...

  ȣƮ  DNS ȮϿ ˻ϱ ؼ /etc/nsswitch.conf
    'hosts:' 'dns' ߰Ǿ ־ Ѵ. ٷ κ
  OS ⺻ Ǿ , Ȯ ϱ  Ȯ.

       hosts:      files dns

  ־ (files, dns) ˻ õѴ.

  3.2.  Microsoft Windows ýۿ Ŭ̾Ʈ 

  Windows Unix ý /etc/resolv.conf Ͽ شϴ 
    , [׸ 4]  DNS    ִ.

       [Image]
       [׸ 4] Windows NT Resolver 

  DNS ϵ PC ȣƮ 'ȣƮ ̸' ִ´. Unix ý
  resolv.conf ϰ Ͽ, '' 'domain', 'DNS  ã
  ' 'nameserver', ' Ƚ ã ' 'search' Ʈ
  شѴ.

  4.    (Domain Parenting & Delegation)

   迭縦   , 迭縦 'www.core.nobreak.com'
     зϿ  ʿ䰡 ִ.  ش 迭
  Ʈũ  , ȿ   ش  ش
  迭   ִ.

       [Image]
       [׸ 5] Domain Delegation  Namespace 

  [׸ 5] .'FreeBSD.ORG'     
  Ͽ ϰ ְ, 'KR.FreeBSD.ORG'   Ʈ 
  CORE ξƷ ġŴ , 'doc-kr.core.kr.FreeBSD.org' 
   Ѵ.    ϳ Ӽ   
   Ʈũ Ը Ҿ     
  ü Ʈũ ε巴 Ѵ.

  4.1.  θ Zone   

    ݵ ӵǾ ϴ  ƴϴ.   θ
  Zone ͺ̽ Բ ǵ  ִ. ⼭ ȸ系 
  ׷ 'NMS.NOBREAK.COM' зϰ,  Ʒ DNS  
  ̴.

  * zone-nobreak.com (NS.NOBREAK.COM)
  nms                     IN      MX 10   mail.nms
                          IN      MX 20   mail2.nms
  dns.nms                 IN      A       150.183.110.53
                          IN      MX 10   mail.nms
                          IN      MX 20   mail2.nms
  mail.nms                IN      A       150.183.110.10
  mail2.nms               IN      A       150.183.110.11

   'nms.nobreak.com'  SOA ڵ ʿ䰡 .

  4.2.    

   ش  ϰ   NS ڵ带  ش
   ۷ ־ Ѵ.  'NOBREAK.COM' ο

       * zone-nobreak.com (NS.NOBREAK.COM)
       nms                     IN      NS      ns.nms        ; Delegation
                               IN      NS      ns2.nms
       ns.nms                  IN      A       150.183.110.2 ; Glue Record
       ns2.nms                 IN      A       150.183.110.3

  IP ּҴ A ڵ忡    Ƿ, ݵ ۷ ڵ带
  Ͽ NS Ͽ Ѵ. (: ``۷ ڵ'')

  Ӽ ns.nms.nobreak.com  ƮϿ   ӹ
  ο  primary  ʿϴ.

       * named.boot (NS.NMS.NOBREAK.COM)
       primary         nms.nobreak.com         zone-nms.nobreak.com

  ׸, Zone ͺ̽ 'zone-nms.nobreak.com'  
  ۼѴ.

  * zone-nms.nobreak.com (NS.NMS.NOBREAK.COM)
  @               IN      SOA     ns.nms.nobreak.com. hostmaster.nms.nobreak.com. (
                          1999012901  ;Serial
                          21600       ;Refresh ( 6 hours)
                          1800        ;Retry   (30 minutes)
                          1209600     ;Expire  (14 days)
                          86400)      ;Minimum ( 1 day)
                  IN      NS      ns.nms.nobreak.com.
                  IN      NS      ns2.nms.nobreak.com.
                  IN      MX 10   mail
                  IN      MX 20   mail2

  ns              IN      A       150.183.110.2
  ns2             IN      A       150.183.110.3
  mail            IN      A       150.183.110.10
  mail2           IN      A       150.183.110.11

  dns             IN      A       150.183.110.53
                  IN      MX 10   mail
                  IN      MX 20   mail2

  Ӽ 'ns2.nms.nobreak.com' Secondary ϱ  ƮϿ
   ߰Ѵ.

       * named.boot (NS2.NMS.NOBREAK.COM)
       secondary       nms.nobreak.com  150.183.110.2  sec-nms.nobreak.com

   ns, ns.nms, ns2.nms BIND  , ܺ Ӽ 
   ȮѴ.

       $ nslookup  -type=NS  nms.nobreak.com  ns.kornet.ne.kr
       nms.nobreak.com nameserver = ns.nms.nobreak.com
       nms.nobreak.com nameserver = ns2.nms.nobreak.com

       $ nslookup  dns.nms.nobreak.com  ns.kornet.ne.kr
       Name:    dns.nms.nobreak.com
       Address:  150.183.110.53

  4.3.    in-addr.arpa 

  NMS.NOBREAK.COM   150.183.110 Ѵٰ .

       $ nslookup  -type=NS  183.150.in-addr.arpa
       183.150.in-addr.arpa    nameserver = ns.nobreak.com
       183.150.in-addr.arpa    nameserver = ns2.nobreak.com

    Inverse     Ӱ  
  ϰ ̷.  '183.150.in-addr.arpa'

       * zone-183.150.in-addr.arpa (NS.NOBREAK.COM)
       110             IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.

  ׸, 'ns.nms.nobreak.com' 'ns2.nms.nobreak.com' primary,
  secondary  ְ Inverse Zone  ν, ι 
    ȴ.

       * named.boot (NS.NMS.NOBREAK.COM)
       primary         110.183.150.in-addr.arpa        zone-110.183.150.in-addr.arpa

       * named.boot (NS2.NMS.NOBREAK.COM)
       secondary       110.183.150.in-addr.arpa        150.183.110.2   sec-110.183.150.in-addr.arpa

       * zone-110.183.150.in-addr.arpa (NS.NMS.NOBREAK.COM)
       @               IN      SOA     ns.nms.nobreak.com. hostmaster.nms.nobreak.com. (
                               1999012901  ;Serial
                               21600       ;Refresh ( 6 hours)
                               1800        ;Retry   (30 minutes)
                               1209600     ;Expire  (14 days)
                               86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.

       2               IN      PTR     ns.nms.nobreak.com.
       3               IN      PTR     ns2.nms.nobreak.com.
       10              IN      PTR     mail.nms.nobreak.com.
       11              IN      PTR     mail2.nms.nobreak.com.
       53              IN      PTR     dns.nms.nobreak.com.

  4.4.  Classless in-addr.arpa  (: RFC2317)

    Ʈ иǴ ׸Ʈ Ȥ (octet) 
  Ǿ ,   ι  ӿ ٸ 
  .  ׸Ʈ  210.105.79.1-128  ι 
   ġ ʴ.

    ǻ  ̶, ι ο  ġ ʰ,
  ߾ӿ հϴ  ϳ, IP   ISP Ŭ
  (half) Ǵ  ߰  ϰ Ƿ, ̷ 
  ̿   ذ   Ǿ ϰڴ.

  ù° δ 79.105.210.in-addr.arpa  ־ 129-256(B
  Ҵ) IP  NS ڵ带   NS
  ns.nms.nobreak.com ۷ ش. '79.105.210.in-addr.arpa' 
  Zone  ̽' ۼ  .

  * zone-79.105.210.in-addr.arpa (NS.NOBREAK.COM)
  2               IN      PTR     ns.nobreak.com.
  3               IN      PTR     ns2.nobreak.com.
  ...
  129             IN      NS      ns.nms.nobreak.com.   # 129-254 
                  IN      NS      ns2.nms.nobreak.com.
  ...
  254             IN      NS      ns.nms.nobreak.com.
                  IN      NS      ns2.nms.nobreak.com.

  NS ڵ带   ߱ , NS.NMS.NOBREAK.COM Ʈ
  Ͽ IP 129-254     primary  
  ־ Ѵ.  ŷο  ִ.

       * named.boot (NS.NMS.NOBREAK.COM)
       primary  129.79.105.210.in-addr.arpa  zone-129.79.105.210.in-addr.arpa
       ...
       primary  254.79.105.210.in-addr.arpa  zone-254.79.105.210.in-addr.arpa

  ,  Zone  129.79.105.210.in-addr.arpa - 254.79.105.210.in-
  addr.arpa     ۼǾ Ѵ.

       * zone-129.79.105.210.in-addr.arpa (NS.NMS.NOBREAK.COM)
       @               IN      SOA     ns.nms.nobreak.com. hostmaster.nms.nobreak.com. (
                               1999012901  ;Serial
                               21600       ;Refresh ( 6 hours)
                               1800        ;Retry   (30 minutes)
                               1209600     ;Expire  (14 days)
                               86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.
                       IN      PTR     dns.nms.nobreak.com.

       * zone-130.79.105.210.in-addr.arpa (NS.NMS.NOBREAK.COM)
       @               IN      SOA     ns.nms.nobreak.com. hostmaster.nms.nobreak.com. (
                               1999012901  ;Serial
                               21600       ;Refresh ( 6 hours)
                               1800        ;Retry   (30 minutes)
                               1209600     ;Expire  (14 days)
                               86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.
                       IN      PTR     dhcp.nms.nobreak.com.

  IPv4 4  еǰ, ̰  4° ݿ  Zone
  ̹Ƿ, ߰ ǰ   .

    ӵ IP ŭ Zone ͺ̽ 䱸Ǳ ,
  ŷο δ   ʴµ,  ̷ Ѱ
   ϰ ҰϿ.

    õ  ִ.

       * zone-79.105.210.in-addr.arpa (NS.NOBREAK.COM)
       2               IN      PTR     ns.nobreak.com.
       3               IN      PTR     ns2.nobreak.com.
       ...
       129             IN      CNAME   129.nms.79.105.210.in-addr.arpa.
       ...
       254             IN      CNAME   254.nms.79.105.210.in-addr.arpa.
       nms             IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.

  Namespace 󿡼 Inverse   'in-addr.arpa' , Ϲ
      ̰   .  ǻ arpa
   IP ο ϴ  ̴,  ϰ, ⼭
   ̿ Classless in-addr.arpa ذϰ ִ.

   '129.79.105.210.in-addr.arpa' ̹Ƿ, ᱹ  
  ȴ.

       * named.boot (NS.NMS.NOBREAK.COM)
       primary  nms.79.105.210.in-addr.arpa  zone-nms.79.105.210.in-addr.arpa

       * zone-nms.79.105.210.in-addr.arpa (NS.NMS.NOBREAK.COM)
       @               IN      SOA     ns.nms.nobreak.com. hostmaster.nms.nobreak.com. (
                                       1999012901  ;Serial
                                       21600       ;Refresh ( 6 hours)
                                       1800        ;Retry   (30 minutes)
                                       1209600     ;Expire  (14 days)
                                       86400)      ;Minimum ( 1 day)
                       IN      NS      ns.nms.nobreak.com.
                       IN      NS      ns2.nms.nobreak.com.

       129             IN      PTR     dns.nms.nobreak.com.
       130             IN      PTR     mail.nms.nobreak.com.
       ...
       254             IN      PTR     layla.nms.nobreak.com.

  129-254 PTR ⿡  Ѵ. 79.105.210.in-addr.arpa
  Zone  IP  CNAME ־ ϴ   
  DNS ˰󿡼 ּ  ƴѰ Ѵ.

   ٸ  Ҵ ɰ ϳ Class  Reverse 
   ISP ܰ迡 ̷ ,  ISP Class θ
  ó ϴ°찡 κ̿, ش Class ü  
  ϴ 찡 κ̴.  ̷ 쿡 ӹ 
  Ÿ  Ҵ IP  Ұ   ۷ ־ Ÿ
   ذ  . Ӽ Ͽ Public IP 
  ȣƮ(PC Ͽ) Reverse  ȵǾ  쿡 
    źε  , ش ȣƮ Reverse Resolving
  ̰ ϴµ ũ    ߱ȴ.

  Classless in-addr.arpa Ӱ  ٸ, ټ C Ŭ
   츦 غ. Ѱ , ش ISP 81.105.210.in-
  addr.arpa  Ӽ  û ϴ ̰,  ̷
   ʰ, ⼭ ϴ Ͱ  Namespace ũ ش
  Ʈũ    ǵϿ, Ʈũ  
  ó Ѵ.

  5.  DNS Sendmail

  5.1.  MX(Mail eXchange) ˰

  MX ڵ ش ȣƮ ŵǴ  ٸ ȣƮ  ϵ
  Ѵ.  ȣƮ    , NOBREAK.COM
   ۽ 쿡 Sendmail  ˾ƺ.

       nobreak.com.            IN      MX 10   layla.nobreak.com.
                               IN      MX 20   marie.nobreak.com.
                               IN      MX 20   suzi.nobreak.com.

  1. ȣƮ ش ο    ȮѴ.

  2. layla  õѴ.

  3. marie Ȥ suzi  õѴ.

  4. (3) õ  ȣƮ  õѴ.

  5. ü ť ,  Ⱓ ֱ 2-4  ݺѴ.

    ߸ MX   ϳ, layla ٿǾ marie 
  ޵Ǿ ,  marie Ϲڽ  ȴٴ , ټ
  MX ڵ   ̴. ̷ Ǹ,   
  ȣƮ Ͽ ξ ϸ, ڴ Ź   
  ȮϿ Ѵٴ Ľ ٵ, Ϲ  priority 
  ȣƮ ť׼ ϵ ϱ  ᱹ  ϳ
  ȣƮ(layla)  ȴ.   marie suzi Sendmail 
   ϵ Ǿ   ť׼ Ѵ.

  1. ش (nobreak.com)    ʾƾ Ѵ.

  2.  ش ȣƮ  (Relay) Ͽ Ѵ.

    ʾƾ Ѵٴ  Sendmail w Ŭ(sendmail.cw Ȥ
  sendmail.cf Cw) nobreak.com    ǹϰ, 
  ̶ ŵǴ    ڽ ƴ ,  
      ش ȣƮ  Ѵ. ٷ  OS
  ǵ ⺻ Sendmail ̸ źϵ Ǿ ִµ,
  ̷  ش ȣƮ ť׼  Կ . 
   SMTP  Ÿο     IP(Ȥ )
  ؼ ̸ ϵ ,  ť   
  ǻó ų ش ȣƮ  ϴ  ؼ ̸
  ϵ(  ǹϴ ٸ  𸣰ڴٸ,  IP 
  ̸  ϶) Ͽ Ѵ. (: ``Allowing
  controlled SMTP relaying in Sendmail 8.9'')

  layla  Ҵ  marie ޵Ǵ  ť Ǿ
  鼭,  Ⱓ(Sendmail.cf  Timeout.queuereturn=5d
  ŭ) ֱ(Sendmail  , Ϲ 30 -q30m)
   õȴ.  ݵ layla NOBREAK.COM  
   Ѵ.

  * layla /etc/sendmail.cw (Solaris: /etc/mail/sendmail.cw)
  nobreak.com

  marie suzi 켱 ٴ    ѷ
  ó    ִ. layla ٿǾ  
  marie(Ȥ suzi) ޵ ̰, ش  ť׼ marie
  ٽ MX Ʈ 켱 ԰Ͽ  õ ̴. ᱹ
   suzi ޵ ̰ suzi    ݺѴ.

   ׷? ׷ ִ.  Sendmail   ϱ
  ش  MX Ʈ ľϰ, ڽ  (sendmail.cw
  ϵ) ԵǾ ִ ȮѴ.  ԵǾ ִٸ, ĪǴ
    (ټ Ī   ֱ ) 켱 
   Ͽ ų (MX  ū) ڵ带 MX Ʈ
  Ѵ.

       nobreak.com.            IN      MX 10   layla.nobreak.com.
                               IN      MX 20   marie.nobreak.com. ()
                               IN      MX 20   suzi.nobreak.com.  ()

  ᱹ marie Sendmail ϴ MX Ʈ layla Եǰ,
   ٴ  layla ɶ  ť׵ȴ.

       nobreak.com.            IN      MX 10   layla.nobreak.com.

  ׷  Sendmail ڽ MX Ʈ ã ϸ(sendmail.cw
  'marie.nobreak.com' ϵǾ  ), suzi ʿ
   ߻ ̰,  suzi   Ȳ̶, ᱹ
  ѷ  ִ. Sendmail ̷ ־ Ȳ , ִ
   Ƚ (Sendmail.cf MaxHopCount=17, ⺻ 25) 
  Ƿ, ᱹ marie suzi MaxHopCount  ɸ ý
  (postmaster) ۽ڿ     
   ̴.

       From: Mail Delivery Subsystem
       To: postmaster@marie.nobreak.com
       Subject: Returned mail: Too many hops 26 (25 max):...

       ----- The following addresses had permanent fatal errors -----

        ----- Transcript of session follows -----
       554 Too many hops 26 (25 max):...
       ===========================================================
       Received: from suzi.nobreak.com by marie.nobreak.com ...
       Received: from marie.nobreak.com by suzi.nobreak.com ...
       ...
       Received: from suzi.nobreak.com by marie.nobreak.com ...
       Received: from marie.nobreak.com by suzi.nobreak.com ...
       ...

    ť ýۿ Ͱ  ߻Ͽ  
  ޽̴.

       nobreak.com.            IN      MX 10   layla.nobreak.com.
                               IN      MX 20   marie.nobreak.com.

       From: Mail Delivery Subsystem
       To: postmaster@marie.nobreak.com
       Subject: Returned mail: Local configuration error

       ----- The following addresses had permanent fatal errors -----

        ----- Transcript of session follows -----
       553 marie.nobreak.com. config error: mail loops back to me (MX problem?)
       554 ... Local configuration error
       ===========================================================
       ...

  DNS ϵǾ õǴ ȣƮ sendmail.cw  ʾ
   ߻   Ȯ  ٸ, alias  ȣƮ
  sendmail.cw Ͽ ϱ ٶ.

  5.2.  MX ڵ带  ʴ ȣƮ

  ȣƮ  Ѵٸ MX ڵ带   .

       mailhub         IN      A       210.105.79.107

  ȣƮ mailhub ŵǴ  ٸ ȣƮ  ʿ䰡 
  , ڴ MX ڵ带  ʾҴ.  ̰ 
  ƴ ̷  ͳݻ  MTA mailhub  ۽Ҷ
  ʿ Ʈ  ߻  ִ.

  Sendmail 츦 캸.  Sendmail  Ӽ 
  mailhub lookup(type=any) Ѵ. Authoritative Ȥ Non-authoritative
  Answer A ڵ常 ް ٵ, Authoritative Answer  MX
  ڵ尡   ŷϿ ߰   ش IP 
  õѴ.  MX ڵ尡  Non-authoritative Answer 
  Sendmail  MX ڵ带  ˻Ѵ.  mailhub MX
  ڵ带  ʱ  Ͱ  ʿ Ǹ Ͽ
  ̴.  Ѵٴ       , 
      ؼ mailhub   Ǵ 
  ٶϴ.

       mailhub         IN      A       210.105.79.107
                       IN      MX 10   mailhub.nobreak.com.

  mailhub ڽ   ̱ , ڽ MX ߴ.
  ̷,  ϴ  ȣƮ  ڱ ڽ Ѱ
  ̻ MX ڵ带   .

  5.3.  MX CNAME  ( RFC974 p5)

  MX ڵ带 CNAME ϴ  ſ   ̴.   RFC
   𿡵  MX ڵ CNAME     Ѿ
  Ȯ      ̷  ݵ  ȴٰ 
   ,   ʿ ߰   ߻Ǵ Ʈ
    Ⱓ ߸  νĵǾ ԰, κ
  ù    ġ ⸦ Ѵ.

       layla           IN      MX 10   marie.nobreak.com.
       marie           IN      CNAME   suzi.nobreak.com.
       suzi            IN      CNAME   mailhub.nobreak.com.
       mailhub         IN      A       210.105.79.75
                       IN      MX 10   mailhub.nobreak.com.

       * layla  ϱ  lookup 
       1. lookup layla.nobreak.com   -> return marie.nobreak.com
       2. lookup marie.nobreak.com   -> return suzi.nobreak.com
       3. lookup suzi.nobreak.com    -> return mailhub.nobreak.com
       4. lookup mailhub.nobreak.com -> return 210.105.79.75

   ǥ   븶 ݾ  ٸ, ǥ
  BIND  ̸ ߸ (``layla.nobreak.com'' IN MX points to a
  CNAME marie.nobreak.com)̶ Syslog  ˷ֽø,  MTA
  Sendmail ̸ ( )ϰ ִ.  ,  MTA
  ش ý   ϴ   Ȱֱ ,
  MX CNAME    ʰ,    Ѵ.

       layla           IN      MX 10   mailhub.nobreak.com.
       marie           IN      CNAME   mailhub.nobreak.com.
       suzi            IN      CNAME   mailhub.nobreak.com.
       mailhub         IN      A       210.105.79.75
                       IN      MX 10   mailhub.nobreak.com.

  ,  ۽ Sendmail  ּҿ Ե CNAME 
  ȣƮ  Կ .    ǥõǴ To:
   'user@marie.nobreak.com' ƴ ȯ۾ ۽
  ̷ٴ ̸, ̴ ȥ ߱  ְ,  
  Sendmail Virtual Domain      ߻ų
   ִ.  CNAME  ȣƮ ּҷ 
  ų, CNAME  A ڵ MX ڵ带 ϴ  .

  5.4.  Nonrecursive MX lookup

    , mailhub ޵Ǵ  غ. Ϲ
   mx2 ޵Ǹ   , Sendmail MX ڵ忡
  Nonrecursive ϱ ,   mx1(ݵ A ڵ带 
  Ѵ) ޵ȴ.

       mailhub         IN      MX 10   mx1.nobreak.com.
       mx1             IN      MX 10   mx2.nobreak.com.
                       IN      A       210.105.79.231

   Sendmail MX ڵ带 CNAME Recursiveϰ Ѿưٸ, 
     ϰ ǹǷ, Sendmail MX ڵ带 Ѿư
  ʴ´.

       mailhub         IN      MX 10   mx1.nobreak.com.
       mx1             IN      MX 10   mx2.nobreak.com.
       mx2             IN      MX 10   mailhub.nobreak.com.   ; Loop

  5.5.  Sendmail Virtual Domain 

  ϳ ȣƮ   'nobreak.com' 'kr.freebsd.org' ,
  Ϲ 'nobreak@nobreak.com' 'nobreak@kr.freebsd.org' ڴ
  . ⿡  κ aliases ̺  Ͱ ,
  ο  ŵǴ  ٸ óϴ   ˾ƺ. 
   Sendmail   ʱ⿡, Sendmail   ˰ ִٴ
   ڳ븸 ٷ絵 ϰڴ.  Sendmail ͼġ ʴٸ
   ϱ  RuleSet, m4, aliases, dbm/btree/hash  
  н ʿ  ִ.

  ϰ ϴ  Sendmail 8.8 ̻󿡼 ϹǷ, 
   ġ  ȮѴ.

       $ telnet localhost smtp
       Trying 127.0.0.1...
       220 kfug2.kr.freebsd.org ESMTP Sendmail 8.9.3/8.9.3

   8.8 ٸ,  <ftp://ftp.sendmail.org/pub/sendmail/>
  ֽŹ ϱ ٶ. Sendmail 8.2 ̻󿡼 'domaintable' ǻó
     , ⿡ ٷ ʰڴ.

  5.5.1.  m4  sendmail.cf 

   'sendmail-VERSION/cf/cf/' ýۿ  mc  
  , Virtual Domain  ʿ 'virtusertable', 'genericstable'
  ǻó ߰Ѵ. ۼ mc  Ϲ   δ.

  * generic-bsd4.4.mc   ۼ freebsd.mc 
  divert(0)dnl
  VERSIONID(`@(#)generic-bsd4.4.mc        8.7 (Berkeley) 5/19/1998')
  OSTYPE(bsd4.4)dnl
  DOMAIN(generic)dnl
  MAILER(local)dnl
  MAILER(smtp)dnl
  FEATURE(virtusertable, btree /etc/domainaliases.db)dnl
  FEATURE(genericstable, btree /etc/useraliases.db)dnl

  ϴ RuleSet ϰ, 'genericstable' ǻó ݴ ۽(out-
  bound)Ǵ      ּ(  From:
  ʵ) ϴ RuleSet Ѵ. DNS Forward Zone Reverse
  Zone ϸ ǰڴ.

  ͺ̽ ·  ǹѴ.  ٸ δ
  hash(Berkeley DB) dbm(NDBM) ִµ, ̺   ȿ
  btree(Berkeley DB) > hash(Berkeley DB) > dbm(NDBM) ̴. ӵ 
  btree hash ϱ ؼ Berkeley DB(FreeBSD  
  Unix ⺻ Եȴ) ġǾ ־ ϸ, sendmail makemap
  Ͻ -DNEWDB ÷(Berkeley DB ġǾ ִٸ ڵ -DNEWDB
  ÷װ ȴ) ؾ Ѵ. Berkeley DB ġǾ  
  쿣 -DNDBM ÷(NDBM ̺귯 κ Unix ⺻
  Եȴ)  Ǵµ ̶ dbm Ͽ Ѵ. 
   Berkeley DB GNU GDBM Ǵ 쿣  ¾ 
   DB  ̿  ִ.

  ۼ freebsd.mc    m4(Macro Language Processor)
   sendmail.cf ȯѴ.

       # cd sendmail-VERSION/cf/cf
       # m4 ../m4/cf.m4 freebsd.mc > freebsd.cf
       # cp freebsd.cf /etc/sendmail.cf

    sendmail.cf Ǿ ϴ Ȳ̶,   
  ǻó ϴ  RuleSet Ͽ sendmail.cf 
  Ͽ . (RuleSet ԵǴ ġ ľϱ  m4
  sendmail.cf Ͽ ϱ ٶ)

  * FEATURE(virtusertable, btree /etc/domainaliases.db)dnl
  # Virtual user table (maps incoming users)
  Kvirtuser btree /etc/domainaliases.db

  # handle virtual users (RuleSet 0 Parse1 Ʒ ġ)
  R$+ < @ $=w . >         $: < $(virtuser $1 @ $2 $@ $1 $: @ $) > $1 < @ $2 . >
  R<@> $+ + $* < @ $* . >
                          $: < $(virtuser $1 + * @ $3 $@ $1 $: @ $) > $1 + $2 < @ $3 . >
  R<@> $+ + $* < @ $* . >
                          $: < $(virtuser $1 @ $3 $@ $1 $: @ $) > $1 + $2 < @ $3 . >
  R<@> $+ < @ $+ . >      $: < $(virtuser @ $2 $@ $1 $: @ $) > $1 < @ $2 . >
  R<@> $+                 $: $1
  R< error : $- $+ > $*   $#error $@ $(dequote $1 $) $: $2
  R< $+ > $+ < @ $+ >     $: $>97 $1

  * FEATURE(genericstable, btree /etc/useraliases.db)dnl
  # Generics table (mapping outgoing addresses)
  Kgenerics btree /etc/useraliases.db

  # handle generics database (RuleSet 93 Ʒ ġ)
  R$+ < @ $=G . > $: < $1@$2 > $1 < @ $2 . > @    mark
  R$+ < @ *LOCAL* >       $: < $1@$j > $1 < @ *LOCAL* > @ mark
  R< $+ > $+ < $* > @     $: < $(generics $1 $: $) > $2 < $3 >
  R< > $+ < @ $+ >        $: < $(generics $1 $: $) > $1 < @ $2 >
  R< $* @ $* > $* < $* >  $@ $>3 $1 @ $2                  found qualified
  R< $+ > $* < $* >       $: $>3 $1 @ *LOCAL*             found unqualified
  R< > $*                 $: $1                           not found

  5.5.2.  Forward-map ̺ ۼ

  , ش ȣƮ ϴ  Ŭ w(sendmail.cw)
  Ͽ Ѵ.

       * /etc/sendmail.cw 
       nobreak.com
       kr.freebsd.org

  Table ۼѴ.

       * /etc/domainaliases 
       webmaster@nobreak.com           dipper
       moonhunt@nobreak.com            moonhunt@ieee.org
       cjh@nobreak.com                 error:nouser Unknown User
       @nobreak.com                    nobreak
       @kr.freebsd.org                 %1@xfree86.org

  ּ 'webmaster@nobreak.com'   dipper εǰ,
   ȴ. 'cjh@nobreak.com' ޵Ǵ  ؼ ޽
  'Unknown User' ϸ, ׿ 'nobreak.com' ŵǴ  
    nobreak ޵ȴ. , ڿ ȴ. 
   aliases ϰ Ͽ ټ ڸ ϴ°  ϴ.
       * /etc/domainaliases 
       announce@kr.freebsd.org         announce.ml
       admin@kr.freebsd.org            admin.ml

       * /etc/aliases 
       announce.ml:            :include:/var/ml/announce.ml
       admin.ml:               nobreak, moonhunt@ieee.org

  5.5.3.  Reverse-map ̺ ۼ

  ȣƮ 'kfug2.kr.freebsd.org'϶, ýۿ out-boundǴ 
  ⺻ 'user@kfug2.kr.freebsd.org' From ´.  
  Reverse-map ̺   ּҸ Ѵ.

       * /etc/useraliases 
       nobreak                 nobreak@nobreak.com
       cjh                     cjh@kr.freebsd.org

  5.5.4.  ̺ ȯ  

  ۼ ̺ makemap  dbm/btree/hash · ȯǾ
  Ѵ. ⼭ btree ϿǷ  Ѵ.

       # makemap btree /etc/domainaliases.db < /etc/domainaliases
       # makemap btree /etc/useraliases.db < /etc/useraliases
       # ls /etc/domainaliases* /etc/useraliases*
       /etc/domainaliases      /etc/useraliases
       /etc/domainaliases.db   /etc/useraliases.db

   Sendmail ϰ  Ȯ.

       # kill -HUP `cat /var/run/sendmail.pid`

       # sendmail -bv webmaster@nobreak.com
       webmaster@nobreak.com... deliverable: mailer local, user dipper

       # sendmail -bv cjh@nobreak.com
       cjh@nobreak.com... Unknown User

       # sendmail -bv anybody@kr.freebsd.org
       anybody@kr.freebsd.org... deliverable: mailer esmtp,
       host xfree86.org., user anybody@xfree86.org

  6.  BIND /

  6.1.  BIND ñ׳

  BIND      ñ׳ Ѵ. ñ׳  
  ؼ Ϸ  ϴµ,   /var/named/ Ȥ
  /var/tmp/ 丮 ´.

  o  HUP: BIND  Ѵ.  Ʈ ̳  ͺ̽
      ,  ñ׳ Ѵ.  ̴ BIND ,
     ϴ Ͱ ٸ, Ʈ ϰ  Zone
     ͺ̽(Serial ) Ʈϰ, ĳ Ѵ.

  o  INT:  BIND Ʈ ĳ  ͺ̽ $ORIGIN
     и ϳ  ϴµ,   ͺ̽
     named_dump.db Ϸ Ѵ.

  o  ILL(BIND-8)/IOT(BIND-4): BIND  named.stats Ϸ
     ߸. Ӽ ,  ʿ   ڷᰡ ִ.

  o  USR1:   named.run Ϸ Ѵ. BIND  ñ׳
          ܰ辿 Űµ,  
     ǥϴ   ݾ ϸ, Ϲ  
      ڼ  ϵȴ.

  o  USR2:   Ѵ.

  o  WINCH: BIND ⺻  ֿ ޽ Syslog .  
     ñ׳   ۵ϸ, ûǴ   Syslog
     ⵵ Ѵ.

  6.2.  BIND Syslog ޽

  BIND Syslog  ϻ ˸ ġ  پ
  ޽ . Ӽ Ϲ    
  Syslog ãƳ  ̰ڴ. Syslog /etc/syslog.conf
    ٸ,  /var/log/messages Ȥ /var/adm/messages
  Ͽ ޽ .

  , BIND  , HUP ñ׳ ޾ ,   ϵǴ
  ϻ ޽̴.

       Jan  1  5:33:39 ns named[288]: starting.  named 8.2
       Jan  2 16:57:11 ns named[291]: reloading nameserver
       Feb  5  3:34:31 ns named[289]: named shutting down

  Syslog  ޽  'ð ȣƮ named[PID]: ޽'
   ĸ ϴµ, BIND-4 BIND-8 ׸   Ǵ
  ܾ ޽  ݾ Կ Ѵ.

       Feb  1 11:33:40 ns named[288]: master zone "nobreak.com"
       (IN) loaded (serial 1999012901)

  Zone ͺ̽ ޸𸮿 Ͽ ǹѴ. BIND-4
  zone' Ī Ǿ.

  Žð BIND   Ѵ. (BIND-4 Ϻ  
  OS  ϴ BIND  ǻĸ ⺻  ִ.)

       Feb  2 18:57:12 ns named[291]: USAGE 917949432 917837292
       CPU=1558.86u/491.54s CHILDCPU=921.29u/1228.57s

       Feb  2 18:57:12 ns named[291]: NSTATS 917949432 917837292
       Unknown=3 A=95677 NS=3 SOA=275 PTR=563972 MX=11355 TXT=16 AXFR=10 ANY=17840

       Feb  2 18:57:12 ns named[291]: XSTATS 917949432 917837292
       RR=270905 RNXD=92478 RFwdR=133260 RDupR=505 RFail=8882
       RFErr=0 RErr=75 RAXFR=10 RLame=111437 ROpts=0
       SSysQ=24028 SAns=467186 SFwdQ=221971 SDupQ=255265 SErr=5319
       RQ=689151 RIQ=17 RFwdQ=0 RDupQ=224 RTCP=53 SFwdR=133260
       SFail=290 SFErr=0 SNaAns=189120 SNXD=186481

   ޽ ó  2 ڴ ð BIND ۵ ð
  ǹѴ. '917949432 - 917837292' ϸ,   ð()
    ִ. USAGE CPU  Ÿµ,  CPU 1558ʵ
  (u) 忡, 491ʵ ý(s) 忡 Ͽ  
  ִ. CHILDCPU  ǹε, Ƽ μ ý ƴ϶,
  CHILDCPU 0u/0s  ǥõ ̴. NSTATS XSTATS 'BIND
  Statistics' ڼ ٷ.

       Feb  5 09:39:05 ns named[26674]: Sent NOTIFY for "nobreak.com IN SOA"
       (nobreak.com); 1 NS, 1 A

  BIND-8 Ե Dynamic Update  Primary Secondary Zone
  ͺ̽ Ǿ Ʈ϶  .  ޽
  'nobreak.com'  Zone ͺ̽ ƮǾ ˸ ޽
  ´ٴ ̴.

       Feb  5 09:36:00 ns named[26674]: ns_forw: query(57.132.119.210.in-addr.arpa)
       No possible A RRs

  Resolver û (ι ) ã    ̴.

       Feb  5 09:35:46 ns named[26674]: Lame server on 'ryu.siyon.com'
       (in 'siyon.com'?): [210.105.79.103].53 'ns.mylover.com'

   'siyon.com' 'ns.mylover.com' ӵǾ, ش
  Ӽ Authority  Ǿ   ̴. ̰ ܺ
  Ʈũ Lame Delegation̹Ƿ Ű  ʾƵ .
  6.3.  BIND Syslog / ޽

   ޽ ӽ̽  ũ, ߸ Ӽ
    ޽̴.  ޽   Ÿ Ӽ 
  ̰, ǵ 쵵 ,    ϵ
  Ѵ.

       Feb  3 12:53:27 ns named[291]: ns_forw: query(shpark.co.kr)
       contains our address (ns.nobreak.com:210.105.79.2)

   'shpark.co.kr' ns.nobreak.com(ڽ) ӵǾ,
  Authority Ǿ   ̴.  Ʈũ  Lame
  Delegation ޽̴, ش  Ȯϰ,  ġ ϵ
  Ѵ.

       Feb  5 10:09:01 ns named[26674]: "nobreak.com IN NS"
       points to a CNAME (ns.nobreak.com)

       Feb  5 10:09:11 ns named[26674]: "nms.nobreak.com IN MX"
       points to a CNAME (mail.nobreak.com)

       Feb  5 09:57:15 ns named[26674]: power.nobreak.com has CNAME and other data

  CNAME ߸ 뿡  ̴. Ư MX õ 
  ü ƴ  MTA(:sendmail)  ÿ   
  ֱ ,  ã  ð   Ƿ .
       ,  ޽ Ÿ.

       nobreak.com.    IN      NS      ns.nobreak.com.   ; (X) ns CNAME̴.
       ns              IN      CNAME   mild.nobreak.com.

       nms             IN      MX      mail.nobreak.com. ; (X) mail CNAME ̴.
       mail            IN      CNAME   mhub.nobreak.com.

       power           IN      CNAME   layla.nobreak.com.
                       IN      MX      mhub.nobreak.com. ; (X)߰ڵ尡   .

  CNAME ڵ  ߰ ڵ嵵   , NS/MX/SOA ڵ
  CNAME    .

       Feb  5 09:24:56 ns2 named-xfer[2502]: record too short from
       [210.105.79.2], zone nobreak.com

  Primary NS xfrnets(BIND-4) Ȥ allow-transfer(BIND-8) ɼ,
  Zone Transfer , ش Zone    ̴. ش
  Ӽ ڿ Ͽ, Zone Transfer ϵ Ͽ Ѵ.

  6.4.  BIND Statistics

  Ӽ Ȱ γ 䱸Ǵ  Ӽ  ľϱ
  Ͽ, ֱ  ڷ 䰡 ʿϴ. ⼭ Ӽ  
  м  ˾ƺ Ѵ.  [׸ 6]  timeout(DNS
  ⺻ UDP ϱ )  ߺ  Ѵ.

       [Image]
       [׸ 6] Ӽ  

  BINDκ    ؼ  
  ILL(BIND-8)/IOT(BIND-4) ñ׳ Ѵ. BIND ñ׳  
   /var/named/named.stats Ȥ /var/tmp/named.stats Ѵ.

  # kill -ILL `cat /var/run/named.pid`
  # ls -al /var/named/named.stats
  -rw-r--r--   1 root     root        19832 Mar  8 04:51 /var/named/named.stats
  # cat /var/named/named.stats
  +++ Statistics Dump +++ (920978301) Tue Mar  9 20:18:21 1999
  208719  time since boot (secs)
  3396    time since reset (secs)
  3       Unknown query types
  205739  A queries
  39      NS queries
  916     SOA queries
  802719  PTR queries
  19192   MX queries
  2       TXT queries
  15      AAAA queries
  129     AXFR queries
  29359   ANY queries

  ++ Name Server Statistics ++
  (Legend)
          RR      RNXD    RFwdR   RDupR   RFail
          RFErr   RErr    RAXFR   RLame   ROpts
          SSysQ   SAns    SFwdQ   SDupQ   SErr
          RQ      RIQ     RFwdQ   RDupQ   RTCP
          SFwdR   SFail   SFErr   SNaAns  SNXD
  (Global)
          447781  164719 227112   869     25991
          0       245    125      170586  0
          33963   720395 337570   294284  8122
          1058113 0      337570   190     0
          227112  20791  0        228616  298214

  [210.104.247.129]
          157     0      0        0       10
          0       0      0        147     0
          0       36     146      22      0
          36      0      0        0       0
          11      0      0        0       13

  .
  .
  .

   BIND 8.2   ̴.

       208719  time since boot (secs)
       3396    time since reset (secs)

  BIND   ð  ε(HUP ñ׳ )
    ð ʴ ǥѴ.

       3       Unknown query types

  ˷     Ƚ̴. ̴ ߸ 
  ϰų,   ο ŸԽõ ̴.

       205739  A queries

  A  κ 뿡 䱸ϴ ̸,   䱸ȴ.

       39      NS queries

   BIND Ʈ   Ҷ, NS  Ѵ. ش
   Ʈ  ƴ 쿡 Dig Nslookup   
   û Ѵ.

       916     SOA queries

  SOA  Secondary NS ش Zone ø ȭ ϱ 
  Ѵ.

       802719  PTR queries

  Reverse  䱸ϴ 鿡 ϸ A  Բ  
  ûȴ.

       19192   MX queries

  MX  Sendmail  MTA    ϱ 
  ûѴ.

       2       TXT queries
       15      AAAA queries

  TXT AAAA  Dig Nslookup DNS    ûȴ.

  129     AXFR queries

  AXFR  Secondary Zone Transfer   ûǹǷ,  ġ Zone
  Transfer Ƚ ǹѴ.

       29359   ANY queries

  Any  ٷ Sendmail  ȣƮ A, MX, CNAME  
   Ѵ.

     ȣƮ(Remote Ӽ Stub Resolver) 
   Ÿ.    ǥϴ [Global] ʵ Ʒ  Ȥ
  õ ȣƮ Ǵµ,    ޸𸮸 Һ
   Ϲ ߿ġ ʾ, BIND-8 ⺻ ŵǾ [Global]
  ʵ常 ǥõȴ. ,  ȣƮ  / Ŷ 
  ڼ  ˷ֱ , Ϲ 迡 ľ  
  (Ʈũ  ) ϴµ  Ǳ⵵ Ѵ. 
   Ʈ  ɼ ν  ȣƮ 踦 ϰ  
  ִ.

       * named.conf (BIND-8)
       options {
               host-statistics yes;
       };

  Legend ǥõǴ ڵ  ʵ ǹ̸ Ÿµ, S(Sent)
  ϴ°  ȣƮ ۽ŵ  ǹϰ, R(Received)
   Ѵ.   BIND   ݾ   ִ.

       RR(Sent us an answer) 447781
       RQ(Sent us a query) 1058113

  Ʈ ȣƮ  Ӽ (Answer) Ƚ RR̸,
  (Question) Ƚ RQ̴. RR RQ   ƴϹǷ, RR
  RQ ġ 谡 .

       RNXD(Sent us a negative response) 164719
       SNXD(Sent them a negative response) 298214

  RNXD û   ' '  ޾  Ѵ.
  SNXD ݴ ' '   ̴.

       RFwdR(Sent us a response we had to fwd) 227112
       SFwdR(Forwarded a response to them) 227112
       RFwdQ(Sent us a query we had to forward) 337570
       SFwdQ(Forwarded a query to them) 337570

  Resolver û   Ӽ ӽ̽ ˻Ͽ
   Ʈ Ӽκ   Resolver
  ϴµ, RFwdR Ʈ Ӽκ  (RR) 
   ̰, SFwdR    ̴.  ݴ RFwdQ
  Resolver (RQ)   û̸, SFwdQ  Ʈ
  Ӽ Ǹ  ̴.

       RDupR(Sent us an extra answer) 869
       RDupQ(Sent us a retry) 190
       SDupQ(Sent them a retry) 294284

  Ӽ ٿǾ Timeout ߱ǰų, Ʈũ   ҷ
  ȣƮ Ŷ /ſ  ߻ , ȣƮ ߺ(Retry)
   û ߻  ִ. RDupR Ʈ ȣƮ  Ӽ
   ߺ ([׸ 6] ó ) Ƚ̸, RDupQ 
  Ӽ  ߺ (ش Ǹ ó ó  ¿
  ŵǴ  ) Ƚ̰, SDupQ  Ӽ Ʈ
  ȣƮ û ߺ  ̴.

       RFail(Sent us a SERVFAIL) 5176
       SFail(Sent them a SERVFAIL) 90

  RFail ȣƮ(Remote) ߸ Zone ͺ̽ , ޸ Ҵ
  , Secondary  Expire     SERVFAIL
   Ƚ Ÿ. SFail  Ӽ  ߼۵ SERVFAIL
  ޽̴.

       RFErr(Sent us a FORMERR) 0
       SFErr(Sent them a FORMERR) 0

  RFErr  FORMERR  Ƚ Ÿ. FORMERR  Ʈ
  Ӽ   ִ Ǹ ޾  . SFErr
  ݴ  Ӽ ۽ FORMERR ޽ ̴.  Ʈũ
  Ŷۿ  ߻ ʴ     0 ̴.

       RErr(Sent us some other error) 245
       SErr(Sent failed) 8122

  ŵ SERVFAIL  FORMERR ̿  /۽  ޽
  RErr/SErr Եȴ.

       RAXFR(Sent us an AXFR) 125

  AXFR  Secondary Zone Transfer ϱ   . 
  ȣƮ ׸񿡼  ʵ尡 0  쿡 ش ȣƮ  Ӽ
   ο ؼ Secondary   Ѵ.

       RLame(Sent us a lame delegation) 170586

  ӵ   Authority Ǿ   
  0 ƴϴ.  Ư  Ӽ Ǿ  Primary Ȥ
  Secondary   ̴.

       ROpts(Sent us some IP options) 0

  IP ɼ  Ŷ Ͽ , ROpts Ѵ.

       SSysQ(Sent them a sysquery) 33963

   Ӽ ý  Ƚ̴. ý  Ʈ
  Ӽ(Ʈ Ӽ Ͽ)  Ʈ ϱ  ȴ.

       RIQ(Sent us an inverse query) 0

  RIQ  Reserve Domain û Ƚ, ٷ BIND PTR
  queries Ǿ  ̻  ʴ´.  RIQ ׻ 0̴.

       RTCP(Sent us a query using TCP) 0

  RTCP TCP   ŵ  Ƚ ǹѴ. κ 
  UDP  /ŵǹǷ   0 ų,  ſ 
  ġ Ѵ.

       SAns(Sent them an answer) 720395
       SNaAns(Sent them a non-autoritative answer) 228616

  SAns û (RQ)   Ƚ ϸ,  ĳ
  ߰ߵǾ 쿡 SNaAns īƮȴ.

  6.5.  BIND Bebugging Output

  BIND   ڵ Ʈ ͳͽ 
  ȰǹǷ,  ٸ  ϰų BIND  ľϱ 
   ƴ϶,  ̸  Ϸ  ʿ .  BIND
    ϰ   شȭ ϰ Ѵٸ,  
  м  ̸    ̴.  δ ƴ 
   ؼϴ ⺻ ̵ ҰѴ.

       # kill -USR1 `cat /var/run/named.pid` (or 'ndc trace')
       # ping www.openbsd.org.
       # kill -USR2 `cat /var/run/named.pid` (or 'ndc notrace')
       # ls -al /var/named/named.run
       -rw-r--r--  1 root  bin  1153 Mar 10 00:30 named.run

  BIND USR1 ñ׳    Ѵܰ辿 µ,
      ڼ  ǥϿ ش.  
  /var/named/named.run Ȥ /var/tmp/named.run Ϸ Ǹ, ſ
   ϹǷ ʿ  ٰ ǴܵǴ  USR2
  ñ׳ ̿  Ű ٶ. BIND  
  ٹ ߻ϴ     ϵǹǷ,  ϴ
   ߸µ ణ γ ʿ  ִ. BIND ʱȭ 
  캸 Ѵٸ 'named -d 1 &'  ý Ŀǵ ɼ
  ־ Ѵ.

       datagram from [210.105.79.6].3442, fd 21, len 33;

  ̰ ȣƮ '210.105.79.6' Ʈ 3442  33 byte UDP
  Ŷ  ũ 6  ŵǾ Ѵ. ⼭ ϴ
   ũͶ  IP ּ(Ŷ listen ϴ) bound 
  ڵ鷯 Ѵ.

       req: nlookup(www.openbsd.org) id 28375 type=1 class=1

  û datagram 'www.openbsd.org'  (req)   ִ.
  ü Ŭ IN(class=1)  A(type=1) ڵ û̸ 
  йȣ 28375 Ű.

  req: missed 'www.openbsd.org' as '' (cname=0)

  û ο  ˰ִ ڷᰡ (Ӽ ش ο 
  Authority   , ĳ ã   ) Ѵ.
  'cname=0' 'www.openbsd.org' CNAME  ʾ ϴµ,
    ܰ迡 BIND ش  CNAME θ ˾Ƴ 
  ,   0 ƴ 쿡 CNAME Ű  
  ã´.

       forw: forw -> [198.41.0.10].53 ds=23 nsid=19461 id=28375 5ms retry 4sec

  ü lookup Ͽ   ܰ Ǹ

       datagram from [198.41.0.10].53, fd 21, len 449;
       ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19461
       ;; flags: qr; Ques: 1, Ans: 0, Auth: 12, Addit: 12
       ;; QUESTIONS:
       ;;      www.openbsd.org, type = A, class = IN

       ;; AUTHORITY RECORDS:
       ORG.    518400  IN      NS      A.ROOT-SERVERS.NET.
       ORG.    518400  IN      NS      I.ROOT-SERVERS.NET.
       ORG.    518400  IN      NS      K.GTLD-SERVERS.NET.

       ;; ADDITIONAL RECORDS:
       A.ROOT-SERVERS.NET.     3600000 IN      A       198.41.0.4
       I.ROOT-SERVERS.NET.     3600000 IN      A       192.36.148.17
       K.GTLD-SERVERS.NET.     518400  IN      A       195.8.99.11

   delegation  ۷     µȴ.
   ĳ ȴ.

       resp: nlookup(www.openbsd.org) qtype=1

  ĳ 'www.openbsd.org.' ٽ ã´.

       resp: found 'www.openbsd.org' as 'org' (cname=0)
       resp: forw -> [195.8.99.11].53 ds=23 nsid=19462 id=28375 1ms

  Ϻ  ƴ, ORG   ߰Ͽ ,

  datagram from [195.8.99.11].53, fd 21, len 219;
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19462
  ;; flags: qr rd; Ques: 1, Ans: 0, Auth: 5, Addit: 3
  ;; QUESTIONS:
  ;;      www.openbsd.org, type = A, class = IN

  ;; AUTHORITY RECORDS:
  OPENBSD.org.    172800  IN      NS      ZEUS.THEOS.COM.
  OPENBSD.org.    172800  IN      NS      CVS.OPENBSD.org.
  OPENBSD.org.    172800  IN      NS      NS.SIGMASOFT.COM.

  ;; ADDITIONAL RECORDS:
  ZEUS.THEOS.COM.         172800  IN      A       199.185.137.1
  CVS.OPENBSD.org.        172800  IN      A       199.185.137.3
  NS.SIGMASOFT.COM.       172800  IN      A       209.249.129.35

  ƿԴ.

       resp: nlookup(www.openbsd.org) qtype=1
       resp: found 'www.openbsd.org' as 'openbsd.org' (cname=0)

  ĳ 'www.openbsd.org.' ã  , 'openbsd.org.' 
   ߰ߴ.

       resp: forw -> [199.185.137.3].53 ds=23 nsid=19467 id=28375 22ms
       datagram from [199.185.137.3].53, fd 21, len 272;

  (A) Ͽ. (  1   ǥõǱ
  ,     쿡    
  Ͽ߸ Ѵ)

       send_msg -> [210.105.79.6].3442 (UDP 21) id=28375

   ˻  Ŭ̾Ʈ ν, 28375  
  ó  Ǿ.

  7.  DNS   

  7.1.  NSLOOKUP

  Ӽ ϰ ϴµ ־  ߰ϰ ذϱ 
  Resolver  Ӽ غ ʿ䰡 ִ. κ ýۿ
  ⺻ ġǾ ִ nslookup dig Բ  θ Ǵ Ӽ
   ν,  ޴ ⺻  ϳ̴.
       $ nslookup
       Default Server:  ns.nobreak.com
       Address:  210.105.79.2
       > exit

  nslookup  ȭ Ʈ '>' ǥϰ Ѵ.
  'nslookup' BIND ޸ ϳ  ǿ ϱ 
  'Default NS -> Timeout -> Error'  Ѵ.

  7.1.1.    ˻

  nslookup ⺻ Էµ ο  A ڵ带 ˻ϰ, IP
  ּ(in-addr.arpa) ؼ PTR ڵ带 ˻Ѵ. 'set type=RR'
   A ڵ ̿ ڵ  ˻  , RR(Resource
  Record) A,ANY,CNAME,HINFO,MX,NS,PTR,SOA,TXT    ִ.  
  ANY õ ڵ  ϶  ȣ̴.

       > www.kr.freebsd.org.                 # IP ˻
       Name:    www.kr.freebsd.org
       Address:  150.183.110.39

       > ftp.kr.freebsd.org.
       Name:    www.kr.freebsd.org           # ftp www CNAME
       Address:  150.183.110.39
       Aliases:  ftp.kr.freebsd.org

       > 150.183.110.39                      #  ˻
       Name:    www.kr.freebsd.org
       Address:  150.183.110.39

       > set type=MX                         # MX ڵ ˻
       > kr.freebsd.org.
       kr.freebsd.org  preference = 10, mail exchanger = mail.kr.freebsd.org

       > set type=NS                         # NS ڵ ˻
       > kr.freebsd.org.                     #   Ȯ
       kr.freebsd.org     nameserver = ns.kr.freebsd.org
       kr.freebsd.org     nameserver = ns2.kr.freebsd.org
       ns.kr.freebsd.org  internet address = 150.183.110.2
       ns2.kr.freebsd.org internet address = 150.183.110.3

       > 46.102.39.in-addr.arpa.             # ι   Ȯ
       kr.freebsd.org     nameserver = ns.kr.freebsd.org
       kr.freebsd.org     nameserver = ns2.kr.freebsd.org
       ns.kr.freebsd.org  internet address = 150.183.110.2
       ns2.kr.freebsd.org internet address = 150.183.110.3

  7.1.2.  ⺻   

  nslookup ⺻ recurse  ϱ ,  ش
   Authority  Ư Ӽ  Ǹ Ͽ
  Authoritative (Ӽ ĳ ƴ) Ȯ  ʿ䰡 ִ.
  'server', 'lserver'  ⺻      ִ. 
   ־ Ӽ ּ( ƴ) ã   
   ε, 'server'  ⺻  ϰ, 
  ٸ. 'lserver' Ÿ Ӽ Ī  , ٽ ٸ
  Ӽ ĪϷ ϴµ,  Ӽ  ʾ ش
  Ӽ ּҸ ˻   Ѵ.  .

       $ nslookup
       Default Server:  ns.nobreak.com
       Address:  210.105.79.2

  nslookup  ⺻  'ns.nobreak.com' 'lserver' ɿ
  ־ NS ּҸ ã   ȴ.

       > server ns.jp.freebsd.org.        # ⺻  
       Default Server:  ns.jp.freebsd.org
       Address:  199.100.7.25

       > server ns.nobreak.com.
       *** Can't find address for server ns.nobreak.com: Non-existent host/domain

  ns.jp.freebsd.org  ns.nobreak.com ã  . ̶
  ּҸ ˻Ѵ.

       > lserver ns.nobreak.com.
       Default Server:  ns.nobreak.com
       Address:  210.105.79.2

  Ʈ Ӽ   ϰ  ,  'root' 
    ִ.

       > root
       Default Server:  a.root-servers.net
       Address:  198.41.0.4

  7.1.3.   ó ϱ

  Ӽ Resolver û óϱ , ӽ̽ ˻ϸ,
   Ӽ  ϴµ, nslookup   ƺ
  . Ӽ ͳݻ󿡼  ϸ, Ӽ  
  ǵ ߻ϰ,    ϴ, ü  
    ̴.

  [Image]
  [׸ 7] Ӽó ϱ

  1.

       > set norecurse     # Iterative  ȯ
       > www.kr.freebsd.org.
       Server:  ns.nobreak.com
       Address:  210.105.79.2

       Name:    www.kr.freebsd.org
       Served by:
       - H.ROOT-SERVERS.NET
                    128.63.2.53
                    ORG
       - B.ROOT-SERVERS.NET
                    128.9.0.107
                    ORG
                ...

  2.

       > server h.root-servers.net.
       > www.kr.freebsd.org.
       Server:  h.root-servers.net
       Address:  128.63.2.53

       Name:    www.kr.freebsd.org
       Served by:
       - WHO.CDROM.COM
                 204.216.27.3
                 FREEBSD.ORG
       - NS1.CRL.COM
                 165.113.1.36
                 FREEBSD.ORG
       - NS2.CRL.COM
                 165.113.61.37
                 FREEBSD.ORG

  3.

  > server who.cdrom.com.
  > www.kr.freebsd.org.
  Server:  who.cdrom.com
  Address:  204.216.27.3

  Name:    www.kr.freebsd.org
  Served by:
  - ns.kr.freebsd.org
            150.183.110.2
            kr.freebsd.org
  - ns2.kr.freebsd.org
            150.183.110.3
            kr.freebsd.org

  4.

       > server ns.kr.freebsd.org.
       > www.kr.freebsd.org.
       Server:  ns.kr.freebsd.org
       Address:  150.183.110.2

       Name:    www.kr.freebsd.org
       Address:  150.183.110.39

  7.1.4.  Zone Transfer

  ش  Zone  纻 , Primaryκ Zone
  ͺ̽  ۾ Zone Transfer Ѵ.  ۾ ַ
  Secondary NS  ̷,  󸶳   ȣƮ
  ϵǾ ִ Ȥ Zone   ˻ϱ  ڰ
   ϱ⵵ Ѵ. Zone Transfer Authority  Ӽ
   Ͽ ϹǷ, nslookup 󿡼 ش NS  
  , 'ls'  Ѵ.

  > server ns.kr.freebsd.org.
  > ls -t A kr.freebsd.org      # A ڵ 
  kr.freebsd.org.                server = ns.kr.freebsd.org
  kr.freebsd.org.                server = ns2.kr.freebsd.org
  mail                           150.183.110.32
  mqueue                         150.183.110.33
  www                            150.183.110.39
  www2                           150.183.110.40

  > ls -d kr.freebsd.org        #  ڵ 
  kr.freebsd.org.                SOA   ns.nobreak.com hostmaster.kr.freebsd.org.
                                 (1999031501 21600 1800 1209600 86400)
  kr.freebsd.org.                NS    ns.nobreak.com
  kr.freebsd.org.                NS    ns2.nobreak.com
  kr.freebsd.org.                MX    10   mail.kr.freebsd.org
  kr.freebsd.org.                MX    20   mqueue.kr.freebsd.org
  cvsup                          CNAME www.kr.freebsd.org
  mail                           A     150.183.110.32
  mqueue                         A     150.183.110.33
  ftp                            CNAME www.kr.freebsd.org
  ftp2                           CNAME www2.kr.freebsd.org
  ftp3                           CNAME ftp.free.nobreak.com
  www                            A     150.183.110.39
  www                            HINFO Pentium-200  FreeBSD 2.2.8
  www                            TXT  "Korea FreeBSD Users Group"
  www2                           A     150.183.110.40
  www2                           HINFO Pentium-133MHz  FreeBSD 2.2.8
  www2                           TXT  "Korea FreeBSD Users Group"

  > ls -t MX kr.freebsd.org > MX-kr.freebsd.org   # Ϸ 
  > view MX-kr.freebsd.org                        #   Ȯ

  BIND  'named-xfer' ܺ α׷  Zone Transfer
  Ѵ. Ӽ 忡 Ʈ Ͽ Secondary   
  ó 캸.

       secondary       kr.freebsd.org  210.105.79.2    sec-kr.freebsd.org

  BIND 'secondary'      Ѵ.

       loop(Interval == TTL) {
               named-xfer -z kr.freebsd.org -f /var/named/sec-kr.freebsd.org -s Current_Serial 210.105.79.2
               switch ( $? ) {      // 'named-xfer' ȯ  '$?'  
                       case 0 : OK; // ø , Zone Transfer ʿġ 
                       case 1 : OK; // ø , Zone Transfer  
                       case 2 : ERROR; // Ӽ ã  
                                       // Ȥ Ӽ  Authority  
                       case 3 : ERROR: // ø ,  ī 
               }
               primary  kr.freebsd.org  sec-kr.freebsd.org
       }

     (: Secondary NS's IP) Zone Transfer
  ϰ Ѵٸ, Primary NS ƮϿ   ɼ ش.
  (Zone Transfer ϴ ̱ , ȣƮ   
  ȴ)

       xfrnets  210.105.79.3&255.255.255.255  210.105.80.128&255.255.255.128

  ̰ BIND-4 ε, IP 210.105.79.3 210.105.80.129-254
   Zone Transfer ϶ ǹ̴. BIND-4  IP
      ``IP&Mask''  
  ۼϸ, Ŭ ü ϰ  쿣 '210.105.79.0' 
  ũ Ͽ ȴ.

       options {
               allow-transfer { localnets; 210.105.79.3; };
       };

  BIND-8 쿡 ش   Ʈũ, 210.105.79.3 
  ̴. localnets ̸ ٸ δ any, none, localhost 
  ִ.

  7.1.5.  ʱȭ  '.nslookuprc'

  nslookup  '~/.nslookuprc'  ϸ,  о ɼ
  Ѵ. Ź ϴ ɼ ִٸ,    ȭ 
  ְڴ.

       * .nslookuprc  
       set type=NS
       set nosearch
       set debug

  7.2.  DIG

  Dig(Domain Information Groper)  ݸ ¤ .
  Ͽ, Shell Script ַ ȴ.  ns.kornet.ne.kr
   www.nobreak.com A ڵ带 ˻ ̴.

  $ dig [@Ӽ]  [Ÿ] [+ɼ]
  $ dig  @ns.kornet.ne.kr  www.nobreak.com  A
  ;; ANSWER SECTION:
  www.nobreak.com.        16h12m36s IN CNAME  ns.nobreak.com.
  ns.nobreak.com.         1d19h12m27s IN A  210.105.79.2
  ;; AUTHORITY SECTION:
  nobreak.com.            22h17m35s IN NS  ns.nobreak.com.
  nobreak.com.            22h17m35s IN NS  ns2.nobreak.com.
  ;; ADDITIONAL SECTION:
  ns.nobreak.com.         1d19h12m27s IN A  210.105.79.2
  ns2.nobreak.com.        1d1h46m58s IN A  210.105.79.3

  DIG    ANSWER SECTION, ش   
  Ӽ  AUTHORITY SECTION, ׸, ۷緹ڵ   
  ׿  ADDITIONAL SECTION Ͽ ش.

  7.3.  DNSWALK

  Dnswalk Perl ۵ ũƮν  ʴ ȣƮ Ű
  MX, PTR  A, ߸ CNAME, ȿ  ̸, 
  Ʈϸ Ʈ, ʿ䳪 ۷ ڵ, Lame Delegation  Zone
  ͺ̽ پ  ãش. ó ߰ġ  
  ϴµ   ̴. Dnswalk ֽ   ּҿ 
   ִ.

  o  <http://www.cis.ohio-state.edu/~barr/dnswalk/>

       $ dnswalk -raFl freebsd.org.
       Checking freebsd.org.
       Getting zone transfer of freebsd.org. from ns2.iafrica.com...done.
       SOA=implode.root.com    contact=hostmaster.freebsd.org
       FAIL: Cannot get SOA record for pt.freebsd.org from zeus.ci.ua.pt
       (lame?): Connection refused
       BAD: lv.freebsd.org NS ns.fasts.com: lame NS delegation
       BAD: eu.freebsd.org NS server.zsb.th-darmstadt.de: unknown host
       WARN: irc3.freebsd.org CNAME irc.nocturnal.net: CNAME (to nocturnal.net)
       WARN: ns.th.freebsd.org A 203.154.230.20: no PTR record
       WARN: irc2.freebsd.org CNAME va.i-Plus.net: unknown host
       1 failures, 3 warnings, 1 errors.

  Dnswalk ˻縦 ϱ  ش  Zone Transfer  
   Dig Resolver ƾ Ѵ. Delegation 
  󰡸 ˻縦 ϱ  Ŵ  Ѵٸ ѹ
  غ ϴ.

  8.  Miscellaneous

  8.1.  FQDN(Fully Qualified Domain Name)

  FQDN Ȯ  ǥ ĪѴ.  Ʈ ġ 
  θ 䱸ϸ, 'YAHOO.COM.' Է, 'WWW.YAHOO.COM.'
  Է ȣϴ. ׷ ̷ ȣ ϱ  FQDN̶ ܾ
  ϸ, ̴ Namespace 󿡼  ȣƮ ϴ
  θ Ѵ.

       www(ȣƮ), yahoo.com.(θ), www.yahoo.com.(FQDN)

  Ģ  ǥ ӽ̽ θ Ȯ ϱ 
   Ʈ('.' Ʈ ) Ͽ ,  Ʈ ϰ
  Ѵ.

  8.2.  DNS BIND 

  DNS Domain Name System ڷν, л ̹ ý Ѵ.
    Ǯ, θ IP ּҷ ȯִ ̴. ,
  ͳݿ ϴ  Ӽ    Ϻκ
  ϰ,  䱸ϴ Ŭ̾Ʈ Resolver Ģ  л
  ڷ ϴ  ã  ִ ý,   DNS  Ѵ.

  BIND Berkeley Internet Name Domain ڷ, DNS 
  Ʈ ϳ̸鼭, 'ũ'̶ ܾó DNS 
  Ʈ Īϴ  ̱⵵ Ѵ. BIND   ÷
  õǾ,  θ ȴ.

  8.3.  BIND-4(Traditional) BIND-8(Next Generation) 

  BIND 1999 1  BIND-4 BIND-8   Ѵ. 1998
  5 11   4.9.7 Ǹ  BIND-4 
  Ǿ, BIND-8   8.2 ϰ ִ. BIND-8
  RFC2136, RFC1996 Ͽ Ŀ  ũ Ǿ
  ǥǾ.  BIND-8 Űܰ ,  κ 
  ޴ OS  Ⱓ  BIND-4 ϰ Ƿ, 
   ε Ⱓ   ȴ. ,  帧
  BIND-8 Ѿ ִ.

  BIND-4 BIND-8 ܺ ̴, Ʈ  ȭ̴.  BIND-4
  Ʈ  named.boot ̰, BIND-8 named.conf ̴.  Ʈ
   ۼ  ̰ ִ. Ÿ Zone ϰ ĳ  
  ϹǷ, BIND-4 BIND-8 ̱׷̼ Ʈ
  ġϰ, Ʈ  ϴ  ϴ.

  8.4.  Public Domain

   ̶ ϸ ۺ  Ѵ. ̴ ͳ 𿡼
   ϵ ӽ̽   ִ  Ѵ.
  , ӽ̽ ũ    Ӽ Ͽ
  ش Ӽ   resolvingϴ 츦 ϰ ã  
    ȴ. 系 ȵ  Ȥ ȴ.

  8.5.  CNAME 뿡 

  CNAME  ο   DNS  ٸ ǰ δ. A
  ڵ常 ڴ ǰߵ ִ. Ư, CNAME CNAME ϴ
  쿡 ؼ  ڷḶ 'ȴ/ȵȴ'   ǰ 
  ְ, ʱ RFC ̸ ϰ ִ. , BIND implementation
  ̸   Ȯϰ ִµ ̴ Ÿ  񽺸
  Aliasingϴ 츦 Ͽ, CNAME ڵ ſ   ̰
  Ư ȣƮ IP Ǿ  õ ڵ带 ãƴٴϸ 
  ϱ ٴ, CNAME Ͽ  ڵ   ı޽Ű 
   ϰ ȿ̱ ̴. CNAME ڵ (MX, SOA,
  NS ڵ  ʴ°) ؼѴٸ CNAME ſ ϰ
  Ȱ    Ѵ.

  8.6.  Zone ͺ̽ ۼ 

  Ϲ  Ģ ؼ Zone ͺ̽ ۼϸ Ǽ
  ̴µ  ȴ.

  1. TAB   . ̰  ڵ带 ãµ  ȴ.

  2. TTL   ʴ ϰų 2D, 1W   ȣ
      Ϸ Ѵ.

  3. ȣƮ Ǵ    ȣƮ ϰų,  FQDN
     ǥѴ.

       ftp                     IN      MX      mail
       www                     IN      CNAME   power

       ftp.nobreak.com.        IN      MX      mail.nobreak.com.
       www.nobreak.com.        IN      CNAME   power.nobreak.com.

  Ȥ  ȣƮ  FQDN ǥѴ. Ÿ  ȣƮ
  CNAME  찡 ֱ  ̰  Ϲ̰ 
  ȴ.

       ftp                     IN      MX      mail.nobreak.com.
       www                     IN      CNAME   power.nobreak.com.

  4. ϸ, ĺ  Ͽ, ߺ ǵǴ κ 
     Ѵ.

  8.7.  ۷ ڵ (Glue Record)

  ۷ ڵ NS ڵ ڷ ־ A ڵ带 ϸ,
  Ӽ ƮƮ  Ѵ.  

       nms.nobreak.com.        IN      NS      ns.nms.nobreak.com.
       ns.nms.nobreak.com.     IN      A       150.183.110.2       ; ۷ ڵ

  ,   ܺο Ǵ Ӽ NS ۷ ڵ
  'ns.kr.freebsd.org' ̹ ǵǾ Ƿ ۷ ڵ
  'ns.nms.nobreak.com' 'ns.kr.freebsd.org' IP Ͽ ƮƮ
   Ͽ ȵȴ.

       nms.nobreak.com.        IN      NS      ns.nms.nobreak.com. ; (X) ߺ ۷ ڵ
       ns.nms.nobreak.com.     IN      A       210.105.79.2

       nms.nobreak.com.        IN      NS      ns.kr.freebsd.org.  ; (O) ٸ 

  ̸ ߺ ۷ ڵ ϸ, ߺ ۷ ڵ Ӽ ο
  IP ּҷ Űܰų   ư Ѵ. Ӽ  ۷
  ڵ ӽ̽ ϰ Ǵ° .

  8.8.  Lame Delegation

  Lame delegation̶ Namespace 󿡼  ũ Ѵ.

       nms.nobreak.com         IN      NS      ns.nms.nobreak.com.
                               IN      NS      ns2.nms.nobreak.com.

   'nms.nobreak.com'     Ӽ , 
    ϳ Ȥ ΰ ش ο  Authority  ʴ
  ,  Primary, Secondary  ȵǾ  찡 Lame
  delegation شȴ.

  8.9.

  Name Server ǿ   ĳ ϰ ֱ  
  ǰ 䱸Ǿ  Namespace  ʰ ĳ ڷ 
  Ѵ. ĳ ڷ Resolving  TTL(Time To Live) ð
  ȿ ȿϰ, TTL Ŀ ıȴ. Ŭ̾Ʈ 
  Resolving û Ӽ ĳ ڷ    Ǿ ش
   Primary Ӽ  ڷḦ  亯 ־ 찡
  'Authoritative answer'̴.

  8.10.  Positive & Negative Caching

   Ȱ Resolving û    κ ߺȴ.

       $ finger @kfug.kr.freebsd.org
       $ talk nobreak@kfug.kr.freebsd.org

  , Ӽ ѹ ˻   ĳ Ͽ, Ŀ
  û  Ǹ ȿ óϵ Ǿ ִ. ׷ٸ,
   ʴ ο  û  ұ? Ϲ ߸
  ο  û  ߺȴ.    Ӽ 
    ŽϹǷ, ʿ ͳ Ʈ  
  ȴ. , Ӽ ̷ ߸    ĳϿ
  ʿ Ʈ Ѵ. ̸ Negative ĳ̶ ϸ, ݴ ˻
  Ǵ ο  ĳ Positive ĳ̶ Ѵ.

  , Ӽ ĳ  ,  ʱ 
  ͺ̽ Ŀ (kill -HUP) ñ׳ ̿ϵ Ѵ.

  8.11.  Iterative(Nonrecursive) & Recursive Ӽ

  Ӽ Recursive   , Ŭ̾Ʈ(̸ 'Stub
  Resolver' Ѵ) û  Namespace ˻  Ѵ.
   Iterative 忡    (ڽ  ʴ
  ο  û) ,   NS  Ѵ. κ
  Ӽ Recursive  ϸ, Iterative  Ʈ 
  Ӽ  Ӽ(Ӽ ſ Iterative 尡
  )  Ʈ  Ѵ. , Ŭ̾Ʈ
  Iterative   Ӽ   Ƿ, Ӽ
  (:resolv.conf,  DNS ã) ߰Ͽ  ȴ.
  BIND-4 ƮϿ 'options no-recursion' ߰ν,
  Iterative  ȯ  ְ, BIND-8 쿣 options Ʈ
  'recursion no;' Ѵ.

  8.12.  RTT(Round Trip Time) Nameserver 

  Ӽ , 信 ҿǴ ð Round Trip Time̶
  Ѵ.(Recursive Ͽ  ˻ ð ƴϴ) BIND 
  Ÿ Ӽ  RTT  ϰ ִٰ, û ο ټ
  Authority NS  RTT    Ӽ  Ѵ. Authority
  NS鿡  RTT   쿣, ش Ӽ ü
  (ÿ)     Բ ΰ RTT
  Ѵ. RTT  ʹ ش ο  û RTT 
      . ,    Ǵ 
       ش Ӽ  RTT ݾ
  Ų.

  8.13.  ϵī ( RFC1034 p25)

  Zone ͺ̽   ϵī(*)  ȴ.

       *               IN      A       210.105.79.20

  ϵī 'Zone Ÿ  ȣƮ' εǹǷ, Zone 
  ȣƮ鿡 Ǹ Ͽ  ȴ. ̿ õ  Ǽ
    MX ڵ ̴.

       *               IN      MX      mail

  ڴ  ȣƮ ޵Ǵ  Ѱ  ,
  ϵī MX Ͽ, ̰    
  ̴.   ϱ ؼ  ȣƮ MX ڵ带
  ߰Ͽ Ѵ.    ǵ  ȣƮ 
   Ѱ  ̴. (   ִ)

  , ϵī ȣƮ(   ϴ)θ  
  ִ.  .

       www.*           IN      A       210.105.79.20

  ̵    ʴ´.

  8.14.  Serial Number 

  Ŵ  ϴ ޴ Ǽ  ϳ  Ʈ۾
   ߸ Serial ѹ̴. Ϲ  19990205010 
  Ǽ Ե '0' ش ʵ带 ÷ο Ų.  Secondary
  Zone Ⱓ Ʈ   ִ.     ذ 
  ִ.

  1. Secondary  Ѵٸ,  Primary Zone Serial

      Ѵ. Secondary Ǿ ִ Zone (Zone
     Transfer)  BIND  Ѵ.

  2. Secondary Ÿ  Ǿ   Ұ ,

     Zone Serial '0' Ѵ. Secondary '0' Serial 
     Zone ؼ,  Ʈ ϹǷ, Refresh ֱ⸸ŭ
     ٸ , ٽ  Serial ϸ ȴ.

       nslookup  -type=SOA  kr.freebsd.org  ns2.nobreak.com

  Secondry  ִ ش Zone Serial ȣ   Ȯ 
  ִ.

  8.15.  IP   TTL 

   ǰִ Ʈũ ߿  ȴٸ,   ش
  ȣƮ TTL ӽ÷ 10(6000sec)  ߾ δ  .

       www     6000    IN      A       210.105.79.6

  Ÿ Ӽ ƿ ĳ ʵ ϱ  TTL 0 ϴ ͵
   , Ŭ̾Ʈ ش  ＼   ݺǴ
  Resolving ϱ , ٶ  ƴϴ.  Maximum
  Propagation Delay Time( TTL +  SOA Refresh) ŭ
  ٸ , ۾(IP )ϸ Ǵµ,  Ʈũ 
  ۵Ǹ ġ  ߰ ̵ ߻ϹǷ, Ʈũ  Ķ,
  1-2  ڿ TTL  ϴ  . ش Zone  
  ȣƮ  쿣, SOA ڵ Minimum Ͽ Ϸ
    ְڴ.

  8.16.  ̷    (Load Sharing Between Mirrored
  Servers)

   Ʈ   ,  ذåν ټ ̷
   Ͽ, ϸ дŰ    ִ. ,
  ̷  ̷  ڿ ȫϿ  ϰ
  ̵ϴµ   ð ҿǰ,   й踦
  ϱⰡ ̵  ִ. ׷ ȭ ǥ ȣ 񽺿
  ,  û  ̷  ִ ǥ 
    ִµ, ⿡   ҰѴ. Shuffle Addresses̶
  Ҹ  Ư  BIND 4.9  ȴ.

       www             180     IN      A       210.105.79.101
                       180     IN      A       210.105.79.102
                       180     IN      A       210.105.79.103

  ϳ ȣƮ  IPּҸ ־ , Ӽ ش
  ο     κ   Ѵ.

       $ nslookup www.nobreak.com
       Name:    www.nobreak.com
       Addresses:  210.105.79.101, 210.105.79.102, 210.105.79.103

       $ nslookup www.nobreak.com
       Name:    www.nobreak.com
       Addresses:  210.105.79.102, 210.105.79.103, 210.105.79.101

       $ nslookup www.nobreak.com
       Name:    www.nobreak.com
       Addresses:  210.105.79.103, 210.105.79.101, 210.105.79.102

  ̰ ε ߷(Load Balancing) ƴ, Ŭ̾Ʈ 3
    ϰ ӵǹǷ, ϸ ϴ ȿ  
  ְ,  ܺηδ ǥ θ ˸ ǹǷ,  Ȯ 
  ҿ ϴ.      κ  ʴ
  Ӽ Ͽ TTL  å(TTL Ͽ ٽ û
  )ϴ ͵ .

  ϳ δ ټ CNAME ϴ ̴. Ģ
  ټ CNAME źεǱ , ݵ   Ʈ Ͽ 
  ɼ ־ Ѵ.

  options {
          multiple-cnames yes;
  };

  ̰ BIND-8  ϸ, ǥ YAHOO(www.yahoo.com)
  ̷  ȴ.

       www             180     IN      CNAME   www1.nobreak.com.
                       180     IN      CNAME   www2.nobreak.com.
                       180     IN      CNAME   www3.nobreak.com.
       www1            180     IN      A       210.105.79.101
       www2            180     IN      A       210.105.79.102
       www3            180     IN      A       210.105.79.103

  ټ A ڵ  Resolver  NS Authority NS ټ
  IP( κ) Ѱܹ޾ ĳ    üε 
  κó , ټ CNAME   NS   ּҸ
  Ѱܹޱ  ü  κ Ұϸ, TTL  
  ش Resolver ϳ ּҸ ϰ ȴ.

  o  Authority NS  Ͽ 

       $ nslookup  www.nobreak.com  ns.nobreak.com
       Name:    www1.nobreak.com
       Address:  210.105.79.101
       Aliases:  www.nobreak.com

       $ nslookup  www.nobreak.com  ns.nobreak.com
       Name:    www2.nobreak.com
       Address:  210.105.79.102
       Aliases:  www.nobreak.com

       $ nslookup  www.nobreak.com  ns.nobreak.com
       Name:    www3.nobreak.com
       Address:  210.105.79.103
       Aliases:  www.nobreak.com

  o  NS ĳ ޾ƿ 

       $ nslookup  www.nobreak.com  ns.kornet.ne.kr
       Name:    www2.nobreak.com
       Address:  210.105.79.102
       Aliases:  www.nobreak.com

       $ nslookup  www.nobreak.com  ns.kornet.ne.kr
       Non-authoritative answer:
       Name:    www2.nobreak.com
       Address:  210.105.79.102
       Aliases:  www.nobreak.com

  , ε ߷ ϱ ؼ ý Ͽ  
  ϴ 谡  ʿϴ.

  9.  Bibliography

  1. Paul Albitz & Cricket Liu, ``DNS and BIND 3rd Edition'', O'Reilly &
     Associates, Inc., ISBN 1-56592-512-2, Sep 1998

  2. Paul Albitz, Matt Larson & Cricket Liu, ``DNS on Windows NT'',
     O'Reilly & Associates, ISBN 1-56592-511-4, Oct 1998

  3. Bryan Costales & Eric Allman, ``sendmail 2nd Edition'', O'Reilly &
     Associates, ISBN 1-56592-222-0, Jan 1997

  4. Bryan Costales & Eric Allman, ``sendmail Desktop Reference'',
     O'Reilly & Associates, ISBN 1-56592-278-6, Mar 1997

  5. H. Eidnes, G. de Groot & P. Vixie, "Classless IN-ADDR.ARPA
     delegation", RFC2317, Mar 1998

  6. M. Andrews, ``Negative Caching of DNS Queries (DNS NCACHE)'',
     RFC2308, Mar 1998

  7. O. Vaughan, ``A Legal Basis for Domain Name Allocation'', RFC2240,
     Nov 1997

  8. M. Hamilton, ``Use of DNS Aliases for Network Services'', RFC2219,
     Oct 1997

  9. R. Elz, R. Bush & S. Bradner, "Selection and Operation of Secondary
     DNS Servers", RFC2182, Jul 1997

  10.
     S. Thomson, Y. Rekhter & J. Bound, "Dynamic Updates in the Domain
     Name System (DNS UPDATE)", RFC2136, Apr 1997

  11.
     P. Vixie, "A Mechanism for Prompt Notification of Zone Changes (DNS
     NOTIFY)", RFC1996, Aug 1996

  12.
     C. Everhart, L. Mamakos & R. Ullmann, "New DNS RR Definitions",
     RFC1183, Oct 1990

  13.
     P. Mockapetris, "Domain Names - Implementation and Specification",
     RFC1035, Nov 1987

  14.
     P. Mockapetris, ``Domain Names - Concepts and Facilities'',
     RFC1034, Nov 1987

  15.
     M. Lottor, ``Domain Administrators Operations Guide'', RFC1033, Nov
     1987

  16.
     M. Stahl, ``Domain Administrators Guide'', RFC1032, Nov 1987

