DNS 관련일을 하게 되면 자연적으로 도메인과 많은 관련성이 있습니다.
특히 도메인을 이해하기 위해서는 Registry-Registrar 개념과 DNS 위임구조를 알아야 합니다.
도메인의 위임정보를 알기 위해서 WHOIS라는 서비스를 제공하고 있습니다.
아주 오래된 프로토콜로 TCP 43번 포트로 제공하고 있는 프로토콜입니다.
(DNS가 53번이므로 외우기도 쉽습니다.)
해당 프로토콜에 대해서는 영문위키를 보면 금방 이해를 할수 있으며, 간단히 telnet 으로도 확인이 가능합니다.
Socket에서 TCP Client 정도만 제작가능하시면 바로 제작이 가능합니다.
이러한 WHOIS 정보는 TLD별로 제공이 되고 있으며, 아래와 같은 규칙을 가지고 있습니다.
whois-servers.net provides DNS alias records (CNAME) for TLD WHOIS servers of the form
.whois-servers.net. [stone@localhost ~]$ telnet com.whois-servers.net 43 Trying 199.7.49.74... Connected to com.whois-servers.net (199.7.49.74). Escape character is '^]'. netpia.com Whois Server Version 2.0 Domain names in the .com and .net domains can now be registered with many different competing registrars. Go to http://www.internic.net for detailed information. Domain Name: NETPIA.COM Registrar: NETPIA.COM, INC. Whois Server: whois.ibi.net Referral URL: http://www.ibi.net Name Server: NS.NETPIA.COM Name Server: NS2.NETPIA.COM Status: clientDeleteProhibited Status: clientTransferProhibited Updated Date: 10-mar-2012 Creation Date: 01-apr-1998 Expiration Date: 31-mar-2013 >>> Last update of whois database: Mon, 17 Sep 2012 15:01:00 UTC <<< NOTICE: The expiration date displayed in this record is the date the registrar's sponsorship of the domain name registration in the registry is currently set to expire. This date does not necessarily reflect the expiration date of the domain name registrant's agreement with the sponsoring registrar. Users may consult the sponsoring registrar's Whois database to view the registrar's reported date of expiration for this registration. TERMS OF USE: You are not authorized to access or query our Whois database through the use of electronic processes that are high-volume and automated except as reasonably necessary to register domain names or modify existing registrations; the Data in VeriSign Global Registry Services' ("VeriSign") Whois database is provided by VeriSign for information purposes only, and to assist persons in obtaining information about or related to a domain name registration record. VeriSign does not guarantee its accuracy. By submitting a Whois query, you agree to abide by the following terms of use: You agree that you may use this Data only for lawful purposes and that under no circumstances will you use this Data to: (1) allow, enable, or otherwise support the transmission of mass unsolicited, commercial advertising or solicitations via e-mail, telephone, or facsimile; or (2) enable high volume, automated, electronic processes that apply to VeriSign (or its computer systems). The compilation, repackaging, dissemination or other use of this Data is expressly prohibited without the prior written consent of VeriSign. You agree not to use electronic processes that are automated and high-volume to access or query the Whois database except as reasonably necessary to register domain names or modify existing registrations. VeriSign reserves the right to restrict your access to the Whois database in its sole discretion to ensure operational stability. VeriSign may restrict or terminate your access to the Whois database for failure to abide by these terms of use. VeriSign reserves the right to modify these terms at any time. The Registry database contains ONLY .COM, .NET, .EDU domains and Registrars.Connection closed by foreign host. [stone@localhost ~]$
보다 확실한 방법은 IP와 주소 정보를 관할하는 IANA의 WHOIS 서버를 통해서 확인을 하면 보다 확실합니다.
The IANA whois server at whois.iana.org provides information on each TLD including the whois server.
[stone@localhost~]$ telnet whois.iana.org 43 Trying 192.0.47.59... Connected to whois.iana.org (192.0.47.59). Escape character is '^]'. kr % IANA WHOIS server % for more information on IANA, visit http://www.iana.org % This query returned 1 object domain: KR organisation: Korea Internet & Security Agency (KISA) address: 12F, Daedong Bldg, 109 Jungdae-ro, Songpa-gu address: Seoul 138-950 address: Korea, Republic Of contact: administrative name: Kilnam Chon organisation: Korea Network Information Center (KRNIC) address: 12F, Daedong Bldg, 109 Jungdae-ro, Songpa-gu address: Seoul 138-950 address: Korea, Republic Of phone: +82 10 8581 3514 fax-no: +82 2 405 5419 e-mail: chonkn@gmail.com contact: technical name: Director of Internet Technology Team organisation: Korea Internet & Security Agency (KISA) address: 12F, Daedong Bldg address: 109 Jungdae-ro, Songpa-gu address: Seoul 138-950 address: Korea, Republic Of phone: +82 2 405 6470 fax-no: +82 2 405 5119 e-mail: techc@kisa.or.kr nserver: B.DNS.KR 61.74.75.1 nserver: C.DNS.KR 203.248.246.220 nserver: D.DNS.KR 203.83.159.1 nserver: E.DNS.KR 2001:dcc:5:0:0:0:0:100 202.30.124.100 nserver: F.DNS.KR 218.38.181.90 nserver: G.DNS.KR 2001:dc5:a:0:0:0:0:1 202.31.190.1 ds-rdata: 17625 7 2 FB939059F4B67BBA1E8AC37E35811E506488B2D8CFF807AF873B2116B5676B5C whois: whois.kr status: ACTIVE remarks: Registration information: http://www.nic.or.kr/ created: 1986-09-29 changed: 2011-11-23 source: IANA Connection closed by foreign host. [stone@localhost ~]$