1. Name Resolution
Domain Name System

2. Learning Objectives
Provide an overview of the Domain Name System (DNS)
Describe the features of DNS in Windows 2000
Install the DNS server
Configure a DNS server
Create resource records manually
Configure a client to use DNS
Manage, monitor, and troubleshoot DNS

3. DNS Overview Host names DNS
Simple names used as aliases for IP addresses
DNS
Hierarchical naming system used to resolve host name to IP address mapping
Contains resource records
Primary name resolution method in Windows 2000
Host files and DNS perform the task of translating from names (host names) to IP addresses

4. Host Files Text files that contain host name to IP address mapping
Used to perform host name to IP address resolution
Precursor to the DNS system
Without host name resolution, users cannot access Internet or intranet resources via Fully Qualified Domain Names (FQDN)

5. Ways to Perform Host Name to IP Address Resolution

6. DNS Structure Root-level domain Top-level domains Second-level domains
Represented by a period
Usually not shown on FQDN
Top-level domains
Second-level domains
Subdomains
Individual hosts

7. DNS Hierarchical Structure

8. Top-level Domains
Organizational domains created by designers of the Internet to simplify the naming and logical structure of the DNS namespace

9. Second-level Domains and Subdomains
Where companies register their names with a name registration company
Gives the company authority to create subdomains to further divide the domain namespace

10. DNS Zones Zone of authority DNS zone
Portion of the DNS namespace that an organization controls
DNS zone
Portion of the DNS namespace that can be administered as a single unit
Each zone has a primary name server that holds the DNS zone file

12. DNS Zones Primary name servers Secondary name servers
Hold a read/write copy of the zone file
Secondary name servers
DNS servers configured to hold a read-only copy of the primary name server’s DNS zone file
All networks should minimally have a primary and a secondary DNS name server

13. DNS Servers Can be configured as caching-only servers
Hold two types of DNS zones:
Forward lookup zones (host name to IP address mapping)
Reverse lookup zones (IP address to host name mappings)

14. DNS System Roles available to computers in DNS system
DNS servers that answer client requests
DNS resolvers; clients that initiate requests
Types of requests or queries
Recursive: DNS client to DNS server
Iterative: DNS server to DNS server
Inverse: Find a host name from a Known IP address

15. Resource Records
Used within the actual zone files to point to particular resources such as hosts, mail exchangers, and name servers

16. Resource Records
continued

17. Resource Records

18. Windows 2000 DNS Supports incremental zone transfers
Primary DNS servers send just the changes in the DNS database to a secondary server; conserves network bandwidth
Supports dynamic DNS as defined in RFC 2136
Allows clients to register DNS information automatically with a DNS server
Supports dynamic registration of clients that do not support DDNS through use of a service such as the Windows 2000 DHCP service

19. Installing DNS Service
Prerequisites
Static IP address
Subnet mask
Default gateway
Set the domain name suffix on the server

20. Setting the Domain Name Suffix on the Server

21. Installing DNS Service
Use Optional Networking Components, accessible via the Advance menu in Network and Dial-up Connections

22. Installing DNS Service

23. Installing DNS Service
Double-click Networking Services in the Windows Optional Networking Components Wizard and select the DNS service
DNS management console is added to the Administrative Tools folder

24. Installing DNS Service

25. Configuring Zones for Dynamic Updates
By default, standard zones on Windows 2000 DNS servers do not support dynamic registration

26. Configuring Zones for Dynamic Updates
Once configured to accept dynamic updates, all zones can allow Windows 2000 computers to create their own A records
If your network uses DHCP, you can configure DHCP servers to register PTR records for Windows 2000 clients and A and PTR records for non-Windows 2000 clients

27. Configuring Zones for Dynamic Updates

28. Creating Resource Records Manually

29. DNS Client Configuration
For clients with static IP addresses
Manually configure a Preferred DNS server and an Alternate DNS server in TCP/IP properties DNS configuration tab for Windows 95/98 clients
For DHCP clients
Configure DNS options for the scope that the client will obtain an IP address from

30. Basic Manual DNS Configuration for Windows 2000 Clients

31. Troubleshooting DNS
Use nslookup from the command prompt

32. Dynamic Host Configuration Protocol
Easy IP
Dynamic Host Configuration Protocol

33. Learning Objectives
Describe the dynamic host configuration protocol (DHCP)
Describe the dynamic IP leasing process
Configure a client to use DHCP
Install the DHCP server service
Configure scopes within the DHCP server service
continued

34. Learning Objectives Define and create scope options
Authorize a DHCP server in Active Directory
Configure DHCP for integration with DNS
Manage, monitor, and troubleshoot DHCP

35. Overview of DHCP
Provides an easy way for network administrators to provide IP addressing information for network clients
Reduces the work associated with moving clients between subnets
DHCP server service can be used to create a pool of IP addresses known as scopes that can be dynamically assigned to clients
Options can include default gateway address, or a DNS and a WINS server address

36. DHCP Lease Process
Discover
Offer
Request
Acknowledgment

37. Step 1: DHCPDiscover

38. Step 2: DHCPOffer

39. Step 3: DHCPRequest

40. Step 3: DHCPRequest

41. Step 4: DHCPAcknowledgment

42. DHCP Renewal Process

43. Configuring a Windows 2000 Server with the DHCP Server Service
Configure a static IP address, subnet mask, and default gateway on the server
Install the DHCP server service
Create scopes and, if needed
Create and specify options on a server
Authorize the DHCP server in Active Directory

44. Client Configuration for DHCP
Any client that supports a standard implementation of DHCP can obtain an IP address from a Windows 2000 DHCP server
To configure Windows clients, specify that they obtain an IP address automatically by accessing the Internet Protocols (TCP/IP) properties found under Local Area Connections properties

45. Client Configuration for DHCP

46. Installing the DHCP Server Service
Minimum requirements
Windows 2000 server machine configured with a static IP address, subnet mask, and, on networks with multiple subnets or networks, a default gateway
Range of addresses that can be used to create scopes (ranges of IP addresses configured for lease to clients via DHCP)
Active Directory installed and configured to allow DHCP servers to be authorized in AD

47. Installing the DHCP Server Service
Many ways to install DHCP
One of the easiest ways is to access Network and Dial-up connections via the Start menu or right-click on My Network Places and select Properties

48. Installing DHCP

49. Installing DHCP

50. Installing DHCP
Common problem on networks attempting to implement DHCP: routers do not pass broadcasts
Solutions
Configure a router to pass DHCP traffic, using the command: IP Helper-Address followed by the IP address of the DHCP server command
Place second DHCP server on same segment as the client

51. Router Blocking DHCPDiscover Packets

52. Configuring a DHCP Server per Physical Segment

53. Configuring Scopes

54. Items in the New Scope Wizard
Name and Description
IP Address range
Subnet mask
Add Exclusions
Lease duration
Configure DHCP Options

55. Main Options Used with DHCP

56. DHCP and Active Directory
Create a DHCP object within Active Directory to validate DHCP servers
Requirements
All DHCP servers must run Windows 2000
First DHCP server in your network must be installed as either a domain controller or member server

57. Integrating DHCP and DNS
You can configure DHCP to create Dynamic DNS entries for clients that do not support DDNS
Helps with support of legacy, non-DDNS aware clients
Windows clients can register their own A records but they still rely on the DHCP server to create reverse lookup records

58. Integrating DHCP and DNS

59. Troubleshooting DHCP Misconfigured scopes or options
Use ipconfig/all command to verify client settings and information
Change options within the DHCP snap-in
A stopped DHCP server service
Use the net start dhcpserver command
continued

60. Troubleshooting DHCP A scope that has run out of addresses
Decrease length of lease for the scope
Increase range of addresses in the scope
Renumber entire scope with new, larger range of addresses
Remove some clients from overcrowded network segment
An improperly configured network
Place a DHCP server on each subnet
Implement DHCP forwarding on subnets without DHCP servers