1. DNS hodduc@sparcs

2. 2010 Pre-wheel group seminar : hodduc@sparcs 8. 네트워크, TCP/IP 7. 기타 시스템 관리 10. NFS 9. DNS 11. 프로그래밍 도구 및 쉘 프로그래밍

3. 2010 Pre-wheel group seminar : hodduc@sparcs WHAT IS DNS?

4. What is DNS? DNS Domain Name Service Domain Name System 2010 Pre-wheel group seminar : hodduc@sparcs

5. What is DNS? Q: “143.248.234.103”? A: “ara.kaist.ac.kr” 2010 Pre-wheel group seminar : hodduc@sparcs Q: “ara.kaist.ac.kr”? A: “143.248.234.103” Translation services between two namespaces : Domain name hierachy Internet Protocol (IP) address (IPv4, IPv6) “Where is ara.kaist.ac.kr ?” Your computer DNS Your computer With ara “Go to 143.248.234.103”

6. 2010 Pre-wheel group seminar : hodduc@sparcs DOMAIN NAME SPACE

7. Domain Name Space Subdomains (and so on) Second Level Domain Top Level Domain Root comgooglenaverorgnetinfokrco.krac.krkaistarasparcsotlgo.kror.kredusharejp 2010 Pre-wheel group seminar : hodduc@sparcs Country-code top-level domains(ccTLD) Generic top-level domains (gTLD) Domain Name Space! (≠DNS ) Each node or leaf has 0 or more info about domain name (a.k.a Resource Records, RR)

8. DNS Zone 2010 Pre-wheel group seminar : hodduc@sparcs

9. DNS Zone 2010 Pre-wheel group seminar : hodduc@sparcs Name Server of “ac.kr” zone Name Server of “kaist.ac.kr” zone Name Server of “postech.ac.kr” zone 위임 한국인터넷진흥원 www.kaist.ac.kr = 143.248.5.102 ara.kaist.ac.kr = 143.248.234.103 hodduc.kaist.ac.kr = 143.248.234.77 …… ns.kaist.ac.kr(143.248.1.177) ns.postech.ac.kr(141.223.1. 2) www.postech.ac.kr = 141.223.5.10 bric.postech.ac.kr = 141.223.114.1 ……

10. Naming Convention FQDN(Full Qualified Domain Name) – 루트 도메인부터 해당 노드까지의 각 계층을 모두 표시 – 단, 계층과 계층 사이는. 으로 잇는다 –LDH rule : Letters(a-zA-Z), Digits(0-9), Hyphen –Case Insensitive –May not start or end with Hyphen 2010 Pre-wheel group seminar : hodduc@sparcs

11. Naming Convention ara.kaist.ac.kr 2010 Pre-wheel group seminar : hodduc@sparcs Is it valid? NO ara.kaist.ac.kr. Do not miss root domain! Question: Assume that system’s Default Host : kaist.ac.kr. Someone asks : “Please find hodduc.sparcs.org” 1. hodduc.sparcs.org.kaist.ac.kr ? 2. hodduc.sparcs.org ? 3. Attack japan? (…) Answer : 1. If user wants the second, user should have ask “Please find hodduc.sparcs.org.”

12. Resource Records 2010 Pre-wheel group seminar : hodduc@sparcs

13. Resource Records 2010 Pre-wheel group seminar : hodduc@sparcs Name 도메인 네임 (Key Index) TTL Time To Live. (on cache table) Class Deprecated (‘IN’ only) Type 리소스 레코드 유형 RDATA 실제 데이터. Type 에 따라 다름

14. Resource Types TypeCode 의미 A1 A host address 호스트 주소 NS2 An authoritative name server 네임서버 도메인 네임 지정 CNAM E 5 The canonical name for an alias. Alias 도메인 네임을 설정 SOA6 Marks the start of a zone of authority Zone 의 속성 지정 MX15 Mail exchange 메일 서버의 도메인 네임 지정 2010 Pre-wheel group seminar : hodduc@sparcs 물. 론 훨씬 더 많지만.. 주로 사용하는 것은 정해져 있음. ( 나머지는 구글링 !)

15. Resource Types 2010 Pre-wheel group seminar : hodduc@sparcs

16. PROTOCOL

17. 혹시나 해서 … 2010 Pre-wheel group seminar : hodduc@sparcs PROTOCOL : 표준화된 통신규약

18. 2010 Pre-wheel group seminar : hodduc@sparcs DNS ara.kaist.ac.kr ㄱ ㄱ ara.kaist.ac.kr واسمحوا ara.kaist.ac.kr ★ ☆★☆ ara.kaist.a c.kr ★☆★☆ ara.kaist.ac.kr ★ ☆★☆ ㅡ.ㅡ?ㅡ.ㅡ? ㅡ.ㅡ?ㅡ.ㅡ? Hobbac Hotdog Odduc

19. DNS Lookups 2010 Pre-wheel group seminar : hodduc@sparcs SectionValue HeaderMeta Data Question(Name, Type, Class) Name should be FQDN AnswerRRs that match the (Name, Type, Class) May be multiple answers AuthorityPointing to name servers closer to the target name Optional AdditionalName server believes may be useful to the client Optional Port : UDP 53. 단 동일한 zone 의 NS 동기화 등을 비롯해 큰 자료 전송시 TCP 53 포트도 사용함

20. 직접 보여드립니다 감이 잘 안 오시죠 ? 2010 Pre-wheel group seminar : hodduc@sparcs

22. DNS ARCHITECTURE

23. 2010 Pre-wheel group seminar : hodduc@sparcs

24. Domain Querying 2010 Pre-wheel group seminar : hodduc@sparcs comgooglenaverorgnetinfokrco.krac.krkaistarasparcsotlgo.kror.kredusharejp ara.kaist.ac.kr.kr ?.kr !! ac.kr !! Kaist.ac.kr !! It is 143.248.234.103

25. comgooglenaverorgnetinfokrco.krac.krkaistarasparcsotlgo.kror.kredusharejpcomgooglenaverorgnetinfokrco.krac.krkaistaraharasparcsotlgo.kror.kredusharejp Domain Update 2010 Pre-wheel group seminar : hodduc@sparcs updated

26. USEFUL TOOLS ABOUT DNS 2010 Pre-wheel group seminar : hodduc@sparcs

27. Hosts 2010 Pre-wheel group seminar : hodduc@sparcs

28. Hosts 2010 Pre-wheel group seminar : hodduc@sparcs

29. Hosts 2010 Pre-wheel group seminar : hodduc@sparcs

30. DNSEver 웹 기반 DNS 서버 개인이 직접 네임서버를 구축하기 어려운 경우 ( 호스팅 계정이나 블로그에 도메인을 연결하는 경우 등 ) 2010 Pre-wheel group seminar : hodduc@sparcs

31. Nslookup DNS Server lookup software Linux 에도 있으나 이것만큼은 윈도우가.. Demo 2010 Pre-wheel group seminar : hodduc@sparcs

32. Bind Berkeley Internet Name Daemon 네임 서버 구축 프로그램 2010 Pre-wheel group seminar : hodduc@sparcs 이건 다음 세미나 를 기대하시길.. ‘3’

33. QUESTION 2010 Pre-wheel group seminar : hodduc@sparcs

34. References SPARCS seminar – pipoket-20090728 En.wikipedia.org/Domain_Name_Service “dns 서버운영지침서.pdf” on http://dns.kisa.or.kr/main.jsp └ 강력 추천 ( 무려 한글문서 ) 2010 Pre-wheel group seminar : hodduc@sparcs

35. THANK YOU! hodduc@sparcs 2010 Pre-wheel group seminar : hodduc@sparcs