1. 70-294: MCSE Guide to Microsoft Windows Server 2003 Active Directory, Enhanced Chapter 2: Name Resolution and DNS

2. Guide to MCSE 70-294, Enhanced2 Objectives Describe and identify valid NetBIOS and DNS names Understand and describe how DNS resolves names Install and configure the Microsoft DNS Server Service to work with Active Directory

3. Guide to MCSE 70-294, Enhanced3 Name Resolution Internet Protocol (IP) address Used on the Internet i.e. 207.46.249.222 Contains information needed to contact remote system on IP network Used to determine: On which network particular computer is located For which computer on network data is destined

4. Guide to MCSE 70-294, Enhanced4 Name Resolution (continued) Process of converting human-friendly name into a number that computers can use For example: www.microsoft.com to 207.46.249.222 Allows names to stay constant Numbers such as IP addresses can change from time to time

5. Guide to MCSE 70-294, Enhanced5 Name Resolution (continued) Windows network 2 naming systems: NetBIOS (Network Basic Input Output System) Domain Name System (DNS) NetBIOS Introduced back in Windows 3.x and Windows NT 3.x Only provided for backwards compatibility today Replaced by Domain Name System (DNS)

6. Guide to MCSE 70-294, Enhanced6 Name Resolution (continued) DNS Primary naming system used on Windows Server 2003 network Networks using Active Directory require DNS infrastructure

7. Guide to MCSE 70-294, Enhanced7 NetBIOS 16-character names First 15 characters available for name 16th character reserved to describe particular service or functionality http://www.windowsitpro.com/Article/ArticleID/15257 /15257.htmlhttp://www.windowsitpro.com/Article/ArticleID/15257 /15257.html Can consist of: Letters Numbers ! @ # $ % ^ & ( ) - _ ' { }. ~

8. Guide to MCSE 70-294, Enhanced8 NetBIOS (continued) May not contain: Spaces \ * + = | : ; " ?, Not case sensitive 16th character typically expressed as: Hexadecimal number Surrounded by angle brackets At end of name

9. Guide to MCSE 70-294, Enhanced9 NetBIOS (continued) SUPERCORP Indicates SUPERCORP domain controllers All names are at the same level Known as a “flat” namespace Difficult to manage in large network environment

10. Guide to MCSE 70-294, Enhanced10 NetBIOS (continued) Simplest method to resolve NetBIOS name: Network broadcast Message includes: NetBIOS name computer is looking for Type of service (represented by the 16th character) IP address of computer sending broadcast Not efficient Two computers on different physical networks separated by a router are unable to resolve each other’s NetBIOS names

11. Guide to MCSE 70-294, Enhanced11 NetBIOS Name Resolution

12. Guide to MCSE 70-294, Enhanced12 NetBIOS (continued) IP addresses associated with resolved NetBIOS names are cached for 10 minutes WINS: Database All computers on network register NetBIOS names Computer sends request directly to WINS server

13. Guide to MCSE 70-294, Enhanced13 WINS Configuration

14. Guide to MCSE 70-294, Enhanced14 WINS Database

15. Guide to MCSE 70-294, Enhanced15 NetBIOS (continued) Problems: Flat namespace Impossible to assign authority for part of namespace to different administrators Impossible to split WINS database into multiple smaller pieces

16. Guide to MCSE 70-294, Enhanced16 Domain Name System Hierarchical naming system Most commonly known because of use on Internet Resolves Fully Qualified Domain Names (FQDNs) to IP addresses Control over different parts of the namespace can be given to different organizations or administrators

17. Guide to MCSE 70-294, Enhanced17 Domain Name System (continued) Allows for different parts of namespace to be located on different servers Provides reverse lookup services Ability to identify host’s name by knowing IP address Useful for: Logging and reporting Analysis Configuring certain types of security

18. Guide to MCSE 70-294, Enhanced18 Domain Name System (continued) FQDN made up of two parts: Hostname such as www or hostABC DNS domain suffix such as microsoft.com or supercorp.net DNS namespace Names can contain: Letters Numbers Hyphen (-)

19. Guide to MCSE 70-294, Enhanced19 Domain Name System (continued) Names can contain: Periods (.) Only as separator between different levels in FQDN Restricted to 63 bytes for host name 255 bytes for entire FQDN Must begin and end with either a letter or a number Not case sensitive

20. Guide to MCSE 70-294, Enhanced20 DNS Namespace

21. Guide to MCSE 70-294, Enhanced21 DNS Namespace (continued) Root domain Entire DNS namespace is represented by a single period (.) Located at end of an FQDN Often not entered at all

22. Guide to MCSE 70-294, Enhanced22 DNS Namespace (continued) Top-level domain (TLD) Rightmost part of FQDN Categories: Country code TLDs (ccTLD) Generic TLDs (gTLD) Example: com in www.microsoft.com

23. Guide to MCSE 70-294, Enhanced23 DNS Namespace (continued) Second-level domain (SLD) Subdomain of a TLD Example: microsoft in www.microsoft.com Host Leftmost name in an FQDN IP address assigned to the particular FQDN Example: www in www.microsoft.comwww.microsoft.com Any additional domain levels are referred to as subdomains

24. Guide to MCSE 70-294, Enhanced24 TLD By Country (ccTLD) Each country has been assigned two-letter TLD Examples:.ca for Canada.uk for the United Kingdom Each national government defines rules for its ccTLD

25. Guide to MCSE 70-294, Enhanced25 TLD By Country (continued) Assigned by Internet Assigned Numbers Authority (IANA) Based on list of country codes maintained by International Standards Organization (ISO) www.iana.org/cctld/cctld.htm

26. Guide to MCSE 70-294, Enhanced26 Generic TLD (gTLD) Not tied to any particular country Include very common TLDs, such as:.com.net.org Each of these TLDs has specific criteria governing who can register names within it

27. Guide to MCSE 70-294, Enhanced27 Generic TLD (continued) Currently in use:.aero.biz.com,.coop.edu.gov.info.int mil.museum.name.net.org.pro.arpa domain used to provide reverse lookup services

28. Guide to MCSE 70-294, Enhanced28 TLD Registrars Each TLD Operated by a registrar Registrar collects and manages information Registrar usually charges a fee All subdomains within a public TLD should be registered with registrar

29. Guide to MCSE 70-294, Enhanced29 Understanding the Domain Name System DNS server Answer queries presented by clients about FQDNs Each piece of DNS information is called a Resource Record (RR)

30. Guide to MCSE 70-294, Enhanced30 Understanding the Domain Name System (continued) RR types: Address (A) record Mail exchanger (MX) record Name server (NS) record Start of authority (SOA) records stores zone name server; zone admin; data file version; update checking, etc. RRs are kept in: Text file Database

31. Guide to MCSE 70-294, Enhanced31 Understanding the Domain Name System (continued) Zone Normally includes all RRs for subdomain Could include subdomain and other subdomains within contiguous naming hierarchy Sometimes referred to as “zone files” BIND Acronym for Berkeley Internet Name Domain

32. Guide to MCSE 70-294, Enhanced32 Authoritative Servers Authoritative server DNS server that has zone containing subdomain Never asks another server about subdomain for which it is authoritative Names and IP addresses of at least two authoritative DNS servers provided to registrar

33. Guide to MCSE 70-294, Enhanced33 Authoritative Servers (continued) Delegation Request is passed down to authoritative server from root Primary name server DNS server with a read-write copy of zone Secondary name servers Other DNS servers with read-only copies of zone

34. Guide to MCSE 70-294, Enhanced34 Primary and Secondary Name Servers

35. Guide to MCSE 70-294, Enhanced35 Transferring Information Zone transfer Zone information transferred from primary to secondary DNS server Incremental zone transfers Note: Primary does not mean Authoritative

36. Guide to MCSE 70-294, Enhanced36 DNS Scenario

37. Guide to MCSE 70-294, Enhanced37 The DNS Name Resolution Process Workstation uses IP address for DNS server to send query to DNS server Query types: Recursive Default Client wants the address resolved if at all possible, or an error if it cannot be resolved Iterative Client wants DNS server to respond only with information from that particular DNS server

38. Guide to MCSE 70-294, Enhanced38 Resolving a DNS Query

39. Guide to MCSE 70-294, Enhanced39 Activity 2-2: Tracing DNS Name Resolution Objective: To trace DNS name resolution and referrals from the root servers to the destination Use the Nslookup tool to query DNS servers Manually perform the name resolution process from both the client computer and local DNS server’s perspectives

40. Guide to MCSE 70-294, Enhanced40 Setting Recursion Option

41. Guide to MCSE 70-294, Enhanced41 Common Errors and Misconceptions About DNS Most errors occur in one of three areas: Resource record errors Delegation errors Weak authorities

42. Guide to MCSE 70-294, Enhanced42 Install and Configure DNS for Active Directory Requires good understanding of DNS Three essential functions of DNS that affect Active Directory: Defining the namespace Locating services Resolving names to IP addresses

43. Guide to MCSE 70-294, Enhanced43 Defining the Namespace Active Directory domains use the same namespace as DNS Active Directory domain not the same as DNS domain But uses the same hierarchical system One-to-one relationship between Active Directory domains and DNS domains

44. Guide to MCSE 70-294, Enhanced44 Locating Services netlogon service Runs on domain controller Responsible for registering records in DNS Domain controller registers an A record for name of the domain Allows clients to resolve name of domain to IP address

45. Guide to MCSE 70-294, Enhanced45 Locating Services (continued) Service locator (SRV) record New type of RR used by Active Directory Allows clients to send DNS query specifying type of service DNS server will return the name of computer providing that service

46. Guide to MCSE 70-294, Enhanced46 Resolving Names to IP Addresses Active Directory clients machines Use DNS to resolve host names to IP addresses Used for: Hosts on internal LAN Hosts on extranets Hosts on intranets

47. Guide to MCSE 70-294, Enhanced47 Installing Microsoft DNS Server in Windows Server 2003 Any DNS server software that supports functions required by Active Directory can be used Must support SRV records Incremental zone transfer support recommended Microsoft DNS server: Ships with all versions of Windows Server 2003 Specifically designed to support needs of Active Directory

48. Guide to MCSE 70-294, Enhanced48 Activity 2-5: Creating Zones on the DNS Server Objective: To create a zone to hold the DNS records for your child domain Manually create a DNS zone

49. Guide to MCSE 70-294, Enhanced49 Summary Domain Name System (DNS) is a distributed, scalable, hierarchical system that provides name resolution services for Internet and private networks The DNS namespace is organized into divisions called domains and subdomains DNS data is organized into resource records RRs are grouped into zones

50. Guide to MCSE 70-294, Enhanced50 Summary (continued) Active Directory uses DNS: To define namespace To locate various services by using SRV records To look up IP numbers for FQDNs The Microsoft DNS server can be installed: From Windows 2003 server setup From the control panel Automatically during Active Directory installation