Powered by DNS

¿

nobreak@kr.FreeBSD.org

3rd Edition,  2000 7 21, Revision 3.4

HTML(Divided) HTML(Combined) SGML(DocBook) ASCII

߸   ִٸ ణ ð ҾϿ ڿ ˷ֽñ
ٶϴ. ̰  鿡 ùٸ  ϴµ ū  ˴ϴ.
    http://www.kr.FreeBSD.org/doc/PoweredByDNS/ 
 ,  ȴٸ Ӱ Ȱϼŵ ϴ. This document can be
freely translated and distributed. It's released under the LDP License.

  ------------------------------------------------------------------------

Table of Contents
1. Domain Name System 
     1.1. DNS Namespace
     1.2. Domain Name Resolving
     1.3. θ 밡 ڼ
2. Name Server 
     2.1. Name Server 
     2.2. BIND(Berkeley Internet Name Daemon) ġ
     2.3. ۺ (Public Domain) û
     2.4. ι (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. ҽ ڵ(Resource Record)
          2.5.4. Zone ͺ̽ 
     2.6. Name Server 
     2.7. Name Server  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 
5.  
     5.1. DNS Notify
     5.2. Dynamic Update
     5.3. ̷   
6. DNS Sendmail
     6.1. MX ˰
     6.2. MX ڵ带  ʴ ȣƮ
     6.3. MX CNAME 
     6.4. Nonrecursive MX lookup
     6.5. Sendmail Virtual Domain 
          6.5.1. m4  sendmail.cf 
          6.5.2. Forward-map ̺ ۼ
          6.5.3. Reverse-map ̺ ۼ
          6.5.4. ̺ ȯ  
7. BIND /
     7.1. BIND ñ׳
     7.2. BIND Syslog ޽
     7.3. BIND Syslog / ޽
     7.4. BIND Statistics
     7.5. BIND Debugging Output
8. DNS   
     8.1. NSLOOKUP
          8.1.1.   ˻
          8.1.2. ⺻   
          8.1.3.  ó ϱ
          8.1.4. Zone Transfer
          8.1.5. ʱȭ  .nslookuprc
     8.2. DIG
     8.3. DNSWALK
9. Miscellaneous
     9.1. FQDN(Fully Qualified Domain Name)
     9.2. DNS BIND 
     9.3. BIND-4(Traditional) BIND-8(Next Generation) 
     9.4. ۺ  (Public Domain)
     9.5. CNAME 뿡 
     9.6. Zone ͺ̽ ۼ 
     9.7. ۷ ڵ (Glue Record)
     9.8. Lame Delegation
     9.9. Authoritative answer & Non-authoritative answer
     9.10. Positive & Negative Caching
     9.11. Iterative(Nonrecursive) & Recursive Ӽ
     9.12. RTT(Round Trip Time) Nameserver 
     9.13. ϵī
     9.14. Serial Number 
     9.15. IP   TTL 
10. Bibliography

List of Figures
1-1. Namespace 
1-2.   Resolving
2-1. Ʈũ 
3-1. Windows NT Resolver  
4-1. Domain Delegation  Namespace 
5-1. Maximum Propagation Delay
7-1. Ӽ  
8-1. Ӽó ϱ

  ------------------------------------------------------------------------

Chapter 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 Figure 1-1  ·
Ѵ.

Figure 1-1. Namespace 

[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. Domain Name Resolving

Figure 1-2.   Resolving

[  Resolving]

  TCP/IP Ŷ θ   .  θ
 IP ȯ۾(Resolving) ϰ Ǵµ, Figure 1-2 ̷
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, WWW.YAHOO.COM   IP
     204.71.200.74 亯(authoritative 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

'A-Z', 'a-z', '0-9', '-'    ִ. θ ݵ 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( Network Solutions) )
, ݾ  Ģ  . KRNIC ڷ ϴ
θ  ʴ ݸ ׸Ʈ 63ڱ Ǯ,
Internic ڷ ϴ  ϰ ׸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)

  ------------------------------------------------------------------------

Chapter 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.(
Resolver 忡 Primary Secondary е ʱ⿡ Primary
ε  ϳ ǰ 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"

ó ISC(Internet Software Consortium)  BIND ֽŹ Ȯϰ,
̰ ų   ɰ  Ǿٸ, ׷̵带
ϰ, BIND-4 ġǾ ִٸ, BIND-8 ̱׷̼Ͽ ο 帧
ϴ°͵  ʰڴ.

BIND ġ ſ ϴ. ISC FTPƮ ֽ  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,  
.

     http://www.dns.net/dnsrd/docs/exotic.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. ι (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 

 nobreak.com ο   Ʈũ  ̴.

Figure 2-1. Ʈũ 

[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

directory Ʈ  ϵ ġ θ Ÿ.  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/namedb̴)

    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 , Ѵ ɷ
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.

Figure 2-1 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

0.0.127.in-addr.arpa loopback ּ 127.0.0.1  ̴. loopback
ּҰ  ʴ ý  , 'primary 0.0.127.in-addr.arpa
...'   Ӽ  ִ.     Ҵ C
Class IP  210.105.79  nobreak.com   ̴.

    * 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/products/BIND/docs/  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. ҽ ڵ(Resource Record)

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.

 Figure 2-1 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 .
hostmaster.nobreak.com.  Email ּε, Ϲ Email ǥ '@'
Ʈ ٲپ  ȴ.  Email ش   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    ִ.

   * 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   ̴.

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

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

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

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

   * 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
 ̴. Namespace   NS ڵ ̷ µ, Ŵ
  شϴ κ̹Ƿ, ⼭ ش ο  
 Ÿٰ ˾Ƶ.  ӿ 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 ˰򿡼 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
ִ.

  ------------------------------------------------------------------------

2.5.4. Zone ͺ̽ 

Figure 2-1 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 
ns.nobreak.com.nobreak.com.  ؼѴ.  ns.nobreak.com.  
Ʈ  FQDN ǥϰų, ns   ȣƮ Ͽ Ѵ.
Ʈ Դ Ǽ ſ  ߻ϹǷ, .

  ------------------------------------------------------------------------

2.5.4.1. ȣ ü  Zone ͺ̽ 

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. Name Server  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.

  ------------------------------------------------------------------------

Chapter 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)

'search nobreak.com' ȣƮ ־  Ƚ  
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  ȣƮ /etc/hosts Ͽ ˻ Ѵ. ý ־
(files, dns) ˻ õѴ.

  ------------------------------------------------------------------------

3.2. Microsoft Windows ýۿ Ŭ̾Ʈ 

Windows Unix ý /etc/resolv.conf Ͽ شϴ 
'Ʈũ'   ִ. '' 'Ʈũ' ޴ TCP/IP 
 , Figure 3-1  DNS    ִ.

Figure 3-1. Windows NT Resolver  

[Windows NT Resolver  ]

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

  ------------------------------------------------------------------------

Chapter 4.   (Domain Parenting & Delegation)

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

Figure 4-1. Domain Delegation  Namespace 

[Domain Delegation  Namespace ]

Figure 4-1 .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

nobreak.com  SOA ڵ尡 ״ Ǳ ,   
nms.nobreak.com   SOA ڵ ʿ䰡 .

  ------------------------------------------------------------------------

4.2.   

nms.nobreak.com  Ը Ŀ  лŰ  Ÿ   ش
 ϰ   NS ڵ带  ش  ۷
־ Ѵ.  nobreak.com ο nms  ns.nms.nobreak.com 
 ̴.

    * 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 

nobreak.com  B Ŭ 150.183   Ҵ޾Ұ, 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  110.183.150.in-addr.arpa 
ϱ  Zone ̴.

    * 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  nobreak.com  129-256
nms.nobreak.com  ϴ 쿡 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   Ӽ 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  ̴, nms.79.105.210.in-addr.arpa   
 оϴ  ϰ, ⼭  ̿ Classless
in-addr.arpa ذϰ ִ.

 129.79.105.210.in-addr.arpa  129.nms.79.105.210.in-addr.arpa  CNAME
ϴµ, nms.79.104.210.in-addr.arpa  primary ns.nms.nobreak.com ̹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 210.105.79 -
210.105.81  Ҵ޾Ұ,  81 Ʈũ  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.

  ------------------------------------------------------------------------

Chapter 5.  

5.1. DNS Notify

: RFC1996

BIND-8  ϴ DNS Notify Primary Zone ͺ̽
Ǿ ش Zone Authority  Secondary  ˷־
Primary Secondary Ӽ  ȭ  Ѵ.

BIND-4 BIND-8  ɼ   Zone SOA  õ
Refresh ֱ Secondary Primary Serial  üũϿ Zone Transfer
ϴ ̳. BIND-8 DNS Notify ϸ Ͽ   濡 
Ľð (Maximum Propagation Delay) ּȭ ش.

Primary Zone Ʈ Ǹ BIND ش Zone NS ڵ带 мϿ
ڽ   Ӽ Zone Ʈ Ǿ ˸ Notify
ȣ , Secondary Primary Zone Serial Ͽ Ȯ
Zone transfer  ش Zone ƮѴ.  Secondary DNS
Notify  Ѵٸ "Not Implemented"  Բ ش û
Ѵ.

Figure 5-1. Maximum Propagation Delay

[Maximum Propagation Delay]

BIND-8 ⺻ DNS Notify ִ.     
ü Ȥ Ư Zone ؼ DNS-Notify ġ   ִ.

    options {
        notify no;  // ü ؼ  . (Ʈ yes)
    }

    zone "freebsd.org" {
        type master;
        file "zone-freebsd.org"
        notify no;          // ش ο ؼ  .
    };

    zone "freebsd.org" {
        type master;
        file "zone-freebsd.org"
        notify yes;         // ش ο ؼ  Ҵ.
    };

Authority  ʴ Ӽ Notify Ʈ ϰ  쿣
also-notify ɼ Ѵ.

    zone "freebsd.org" {
        type master;
        file "zone-freebsd.org"
        notify yes;
        also-notify {210.124.149.130;};
    };

RFC1996  DNS Notify û  Secondary Ӽ ش 
Authority  ٸ Ӽ ٽ DNS Notify ȣ  ϴµ
 BIND-8  Ե ʾ ϱ ٶ.  
Ʈũ  Secondary Primary ٷ ġ ϰ ٸ
Secondary ͷ ϴ 츦  Ǿ, ǿ ̷
찡 ſ 幰 ٶ  (Maximum Propagation Delay
)̱⿡ BIND-8    ʹ.

  ------------------------------------------------------------------------

5.2. Dynamic Update

: RFC2136

BIND-8  Ǵ Dynamic Update ش  Authority 
Ӽ  Zone  ġ ʰ ڵ带    
ֵ Ѵ.   ڵȭ ϰų, ں   ǽð
Ͽ ϰų, DHCP ּ-IP Ī  ǽð 
ڵ尡 ,   ʿ䰡 ִ 񽺿 Ư   ְڴ.

Dynamic Update   ⺻  ֱ  
ο  allow-update ɼ ߰ؾ Ѵ.

    zone "freebsd.org" {
        type master;
        file "zone-freebsd.org";
        allow-update { 210.124.149.130; };
    }

Dynamic Update BIND ǿ ԵǾ ִ nsupdate  Ͽ
(non-interactive) Ȥ ȭ(interactive)  ϴ.
ȭ 忡 ־ ɹ (ǹ ɹ)  ϱ
 Է ɹ()  ο ͸ ѹ  ԷϿ Ѵ.
  ɹ ־ ̳ stdin  Է¹޴´. 
nsupdate 밡 ɹ̴.

prereq yxdomain DOMAIN-NAME

     DOMAIN-NAME (ϳ̻ ڵ尡 Ǿ ) ӵ
        ´.

prereq nxdomain DOMAIN-NAME

     DOMAIN-NAME  ڵ嵵 Ǿ   ӵ  
      ´.

prereq yxrrset DOMAIN-NAME [CLASS] TYPE [DATA]

     DOMAIN-NAME ش ڵ尡  ӵ   
     ´. DATA õǾ  쿡 Ȯϰ Ī Ǵ 쿡
      ȴ.

prereq nxrrset DOMAIN-NAME [CLASS] TYPE

     DOMAIN-NAME ش ڵ尡   ӵ  
      ´.

update delete DOMAIN-NAME [CLASS] [TYPE [DATA...]]

     TYPE õ ʾ 쿣 ش DOMAIN-NAME Ҽӵ ڵ带 
     Ѵ. TYPE õ 쿣 ĪǴ ڵ常 ŵȴ.

update add DOMAIN-NAME TTL [CLASS] TYPE DATA...

      ڵ带 ش ο ߰Ѵ.

    $ nsupdate
    > update add freefall.freebsd.org. 3600 IN A 210.124.149.150
    > [Enter]
    ...(messages)...
    > ^D

    $ nsupdate
    > prereq nxrrset freebsd.org. IN MX
    > update add freebsd.org. 3600 IN MX 10 mail.freebsd.org.
    > [Enter]
    ...(messages)...
    > ^D

 A, CNAME  ڵ尡  θ ؼ delete ġ ʰ
add  Է  ڵ Ͱ Էµ ڵ ͷ
üɰŶ   ƾ Ѵ. ߺ A ڵ Է ο
 IP  ̰, CNAME  θ ٸ ڵ尡 
  CNAME addϴ  ش  A, MX  ڵ带
ڵ  ʱ ̴.

Dynamic Update     Ǹ named   ش
Zone ͺ̽  ϵǾ  ÿ   Ծ
  ֵ Ѵ.

Dynamic Update  û ش  Authority  Secondary
 ٸ Secondary Ӽ Primary Ӽ û ϵ
Ǿִ.  ̷ 쿣 Primary allow-update ＼ Ʈ
Secondary ԵǾ ־ Ѵ.

  ------------------------------------------------------------------------

5.3. ̷   

 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
            180 IN  A   210.105.79.104
            180 IN  A   210.105.79.105

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.

    * 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, 210.105.79.104, 210.105.79.105
    Aliases:  www.nobreak.com

    * Ӽ ĳ(Third Party Name Server) ޾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

    $ sleep 180  (TTL    ٸ )

    $ nslookup  www.nobreak.com  ns.kornet.ne.kr
    Non-authoritative answer:
    Name:    www3.nobreak.com
    Address:  210.105.79.103, 210.105.79.104, 210.105.79.105
    Aliases:  www.nobreak.com

    $ nslookup  www.nobreak.com  ns.kornet.ne.kr
    Non-authoritative answer:
    Name:    www3.nobreak.com
    Address:  210.105.79.104, 210.105.79.105, 210.105.79.103
    Aliases:  www.nobreak.com

    $ nslookup  www.nobreak.com  ns.kornet.ne.kr
    Non-authoritative answer:
    Name:    www3.nobreak.com
    Address:  210.105.79.105, 210.105.79.103, 210.105.79.104
    Aliases:  www.nobreak.com


, ε 뷱 ϱ ؼ ý Ͽ  
ϴ ġ Ŭ͸(Clustering) ַ Ͽ Ѵ.

  ------------------------------------------------------------------------

Chapter 6. DNS Sendmail

6.1. MX ˰

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  
 Feature 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 <MAILER-DAEMON@marie.nobreak.com>
    To: postmaster@marie.nobreak.com
    Subject: Returned mail: Too many hops 26 (25 max):...

    ----- The following addresses had permanent fatal errors -----
    <nobreak@nobreak.com>

     ----- 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 <MAILER-DAEMON@marie.nobreak.com>
    To: postmaster@marie.nobreak.com
    Subject: Returned mail: Local configuration error

    ----- The following addresses had permanent fatal errors -----
    <nobreak@nobreak.com>

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

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

  ------------------------------------------------------------------------

6.2. 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   .

  ------------------------------------------------------------------------

6.3. MX CNAME 

: RFC974

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 >
  ------------------------------------------------------------------------

Transfer interrupted!

   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 .  user@marie.nobreak.com 
 , user@mailhub.nobreak.com    ۽ŵǸ, ̴
   ǥõǴ To:  user@marie.nobreak.com  ƴ
user@mailhub.nobreak.com  Ѵ. ߿  ̷ ȯ۾
۽ ̷ٴ ̸, ̴ ȥ ߱  ְ,  
Sendmail Virtual Domain      ߻ų 
ִ.  CNAME  ȣƮ ּҷ  ų, CNAME
 A ڵ MX ڵ带 ϴ  .

  ------------------------------------------------------------------------

6.4. 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

  ------------------------------------------------------------------------

6.5. 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 Feature  
 , ⼭ ϴ Sendmail 8.8 ̻ virtusertable Feature
üǴ ߼̹Ƿ ⿡ ٷ ʰڴ.

  ------------------------------------------------------------------------

6.5.1. m4  sendmail.cf 

 sendmail-VERSION/cf/cf/ ýۿ  mc   ,
Virtual Domain  ʿ virtusertable, genericstable Feature
߰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

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

btree  ش ̺(domainaliases.db) B-Tree(Berkeley DB) 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,    Feature
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

  ------------------------------------------------------------------------

6.5.2. Forward-map ̺ ۼ

, ش ȣƮ ϴ  Ŭ w(sendmail.cw) Ͽ
Ѵ.

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

domainaliases      Virtual User 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,
moonhunt@nobreak.com  ޵Ǵ  moonhunt@ieee.org   ȴ.
cjh@nobreak.com  ޵Ǵ  ؼ ޽ 'Unknown User'
ϸ, ׿ nobreak.com  ŵǴ     nobreak
޵ȴ. , kr.freebsd.org  ŵǴ   xfree86.org  
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

  ------------------------------------------------------------------------

6.5.3. 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

  ------------------------------------------------------------------------

6.5.4. ̺ 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

  ------------------------------------------------------------------------

Chapter 7. BIND /

7.1. BIND ñ׳

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

HUP

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

INT

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

ILL(BIND-8)/IOT(BIND-4)

     BIND 
     ----------------------------------------------------------------------

     Transfer interrupted!

     Ϸ Ѵ. Ӽ ,  ʿ   ڷᰡ ִ.

USR1

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

USR2

       Ѵ.

WINCH

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

  ------------------------------------------------------------------------

7.2. 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 'primary
zone'̶ ǥϿ, BIND-8 Ѿ鼭 'master zone' Ī
Ǿ.

Žð BIND   Ѵ. (BIND-4 Ϻ   OS
 ϴ BIND  Feature 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 .

  ------------------------------------------------------------------------

7.3. 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.

  ------------------------------------------------------------------------

7.4. 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.

Figure 7-1. Ӽ  

[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.

  ------------------------------------------------------------------------

7.5. BIND Debugging 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
'J.ROOT-SERVERS.NET(198.41.0.10:53)'  Ѵ.

    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

J.ROOT-SERVERS.NET  û    Դ. ó 
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 ,
'K.GTLD-SERVERS.NET(195.8.99.11)' Ǹ  Ѵ.

    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

K.GTLD-SERVERS.NET κ   ۷  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;

CVS.OPENBSD.ORG(199.185.137.3)  Ǹ  ,  (A)
Ͽ. (  1   ǥõǱ , 
   쿡     Ͽ߸ Ѵ)

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

 ˻  Ŭ̾Ʈ ν, 28375  
ó  Ǿ.

  ------------------------------------------------------------------------

Chapter 8. DNS   

8.1. 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 /etc/resolv.conf ǵ
ù ° Ӽ ⺻   Ѵ. nslookup BIND ޸ ϳ
 ǿ ϱ  'Default NS -> Timeout -> Error' 
Ѵ.

  ------------------------------------------------------------------------

8.1.1.   ˻

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

  ------------------------------------------------------------------------

8.1.2. 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, lserver  ý ⺻ (nslookup  ʱ
Ǵ)  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  . ̶ lserver
 ý ⺻   ns.nobreak.com  ּ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

  ------------------------------------------------------------------------

8.1.3.  ó ϱ

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

Figure 8-1. Ӽó ϱ

[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
    ...

ORG.  Ǵ Ʈ   ۷ ش.

    (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

  ------------------------------------------------------------------------

8.1.4. 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 
ִ.

  ------------------------------------------------------------------------

8.1.5. ʱȭ  .nslookuprc

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

    * .nslookuprc  
    set type=NS
    set nosearch
    set debug

  ------------------------------------------------------------------------

8.2. DIG

Dig(Domain Information Groper)  ݸ ¤ .
nslookup  ̴ ũ ,  ϰ,  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.

  ------------------------------------------------------------------------

8.3. 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   ִ.

   * 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.

  ------------------------------------------------------------------------

Chapter 9. Miscellaneous

9.1. 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.

  ------------------------------------------------------------------------

9.2. 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.

  ------------------------------------------------------------------------

9.3. 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.

  ------------------------------------------------------------------------

9.4. ۺ  (Public Domain)

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

  ------------------------------------------------------------------------

9.5. 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.

  ------------------------------------------------------------------------

9.6. Zone ͺ̽ ۼ 

Ϲ  Ģ ؼ Zone ͺ̽ ۼϸ Ǽ
̴µ  ȴ.

   * TAB   . ̰  ڵ带 ãµ  ȴ.

   * TTL   ʴ ϰų 2D, 1W   ȣ
      Ϸ Ѵ.

   * 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.

   * ϸ, ĺ  Ͽ, ߺ ǵǴ κ  Ѵ.

  ------------------------------------------------------------------------

9.7. ۷ ڵ (Glue Record)

۷ ڵ NS ڵ ڷ ־ A ڵ带 ϸ, Ӽ
ƮƮ  Ѵ.   ns.nms.nobreak.com  ۷
ڵ̴.

    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.kr.freebsd.org 
 ϴ 쿣, freebsd.org  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° .

  ------------------------------------------------------------------------

9.8. 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.

  ------------------------------------------------------------------------

9.9. Authoritative answer & Non-authoritative answer

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    Non-authoritative answer̰, ĳ ڷᰡ ų,
ڷ TTL Ǿ ش  Primary Ӽ  ڷḦ 
亯 ־ 찡 Authoritative answer̴.

  ------------------------------------------------------------------------

9.10. 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  named
ϸ ĳ Բ . , ϸ Zone ͺ̽
Ŀ (kill -HUP) ñ׳ ̿ϵ Ѵ.

  ------------------------------------------------------------------------

9.11. 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.

  ------------------------------------------------------------------------

9.12. 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.

  ------------------------------------------------------------------------

9.13. ϵī

: RFC1034 p25

Zone ͺ̽   ϵī(*)  ȴ.

    *               IN      A       210.105.79.20

ϵī Zone Ÿ  ȣƮ鿡 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

www.ANYTHING.nobreak.com   Ͽ,  ⸷ ̵
   ʴ´.

  ------------------------------------------------------------------------

9.14. Serial Number 

Ŵ  ϴ ޴ Ǽ  ϳ  Ʈ۾ 
߸ Serial ѹ̴. Ϲ  YYYYMMDDNN ǥδ
4294 ǥ⸦   ִµ, 19990205010  Ǽ Ե '0' ش
ʵ带 ÷ο Ų.  Secondary Zone Ⱓ Ʈ
  ִ.    ذ  ִ.

   * Secondary  Ѵٸ,  Primary Zone Serial 
     Ѵ. Secondary Ǿ ִ Zone (Zone Transfer)
      BIND  Ѵ.

   * 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  ִ.

  ------------------------------------------------------------------------

9.15. IP   TTL 

 ǰִ Ʈũ ߿  ȴٸ,   ش
ȣƮ TTL ӽ÷ 10(600sec)  ߾ δ  .

    www     600     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( SOA Refresh +  TTL, : DNS Notify) 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.

  ------------------------------------------------------------------------

Chapter 10. Bibliography

  1. Paul Albitz & Cricket Liu, "DNS and BIND 2rd Edition", O'Reilly &
     Associates, Inc., ISBN 1-56592-236-0, Dec 1996

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

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

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

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

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

  7. M. Andrews, "Negative Caching of DNS Queries (DNS NCACHE)", RFC2308,
     Mar 1998

  8. O. Vaughan, "A Legal Basis for Domain Name Allocation", RFC2240, Nov
     1997

  9. M. Hamilton, "Use of DNS Aliases for Network Services", RFC2219, Oct
     1997

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

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

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

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

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

 15. P. Mockapetris, "Domain Names - Concepts and Facilities", RFC1034, Nov
     1987

 16. M. Lottor, "Domain Administrators Operations Guide", RFC1033, Nov 1987

 17. M. Stahl, "Domain Administrators Guide", RFC1032, Nov 1987

  ------------------------------------------------------------------------
