1. Windows Name Resolution

2. Describe the different name types available on Windows Server
View and configure NetBIOS names
Describe the host name resolution process
Discuss the different methods used to resolve NetBIOS names
Configure NetBIOS name resolution using the LMHOSTS file and WINS
Troubleshoot name resolution

3. Name Types
WinSock and NetBIOS are the two standard methods used to access network resources
Host name is a name accessed through WinSock
DNS domain names consist of an organization name followed by a top-level domain
To merge with the worldwide DNS lookup system, you must register your domain name with a registrar
Use the hostname command in Windows Server 2008 to view your host name

4. Name Types (continued)

5. Name Types (continued)

6. Name Types (continued)

7. Name Types (continued)
A NetBIOS name is used to access a resource through NetBIOS
All of the networking functions in pre-Windows 2000 operating systems use NetBIOS names
NetBIOS names are limited to 15 characters in length and have a 16th character that identifies the target resource or service
Use the nbtstat –n command to view the NetBIOS names attached to services

8. Name Types (continued)

9. Host Name Resolution
WinSock applications use more than one method to resolve host names to IP addresses
Resolution steps:
Checks to see if the host name being resolved is the same as its own host name
HOSTS file is loaded into cache
DNS cache evaluated
Machine requests information from DNS server
Tries NetBIOS name resolution as a last resort

10. Configuring a HOSTS File for Name Resolution
HOSTS file is a simple text file
Contents of a HOSTS file is a list of IP addresses and host names
IP address on the left, one or multiple spaces, host name on the right
# denotes a comment

11. Configuring a HOSTS File for Name Resolution (continued)

12. Managing the DNS Cache
The DNS cache is queried before DNS is contacted
The DNS cache contains the contents of the HOSTS file as well as previous DNS query results
DNS query results are not stored in cache permanently
To view the contents of the DNS cache, simply run the command ipconfig /displaydns
To purge the cache, simply run the command ipconfig /flushdns

13. Managing the DNS Cache (continued)

14. Using DNS for Name Resolution
Your computer will use whatever DNS server is specified in the TCP/IP settings for name resolution
DNS may use either a forward or reverse lookup scheme

15. Using DNS for Name Resolution (continued)

16. Forward Lookup
The most common task for a DNS server is to resolve a host name to an IP address
Resolving host names within an organization is a two-packet process
13 root servers control the overall DNS lookup process for the entire Internet
A recursive lookup is used whenever the local DNS server does not hold the requested information

17. Forward Lookup (continued)

18. Reverse Lookup Involves the conversion from an IP address to host name
Often performed for the system logs of Internet services
Reverse lookup DNS information is maintained by the organization that has been assigned an entire class of addresses

19. DNS Record Types
DNS records are created on a DNS server to resolve queries
Each type of record holds different information about a service, host name, IP address, or domain
DNS has the ability to hold many different record types

20. DNS Record Types (continued)

21. Using NSLOOKUP The utility NSLOOKUP queries DNS records
NSLOOKUP can be used from a command prompt to resolve host names
NSLOOKUP is most powerful in interactive mode
You can use NSLOOKUP to view any DNS records available for a zone

22. NetBIOS Name Resolution
There is more than one name resolution method
Methods include:
NetBIOS name cache
WINS
Broadcast
LMHOSTS files
Broadcasts can slow down network communication
The NetBIOS name cache and WINS are both used to resolve computer names before the client attempts a broadcast

23. NetBIOS Name Resolution (continued)

24. Using a LMHOSTS File for Name Resolution
LMHOSTS file is a simple text file
The LMHOSTS file stores NetBIOS names and their associated IP addresses
Each entry in the file has the IP address on the left, one or multiple spaces, then the NetBIOS name on the right
Lines that begin with a # symbol are comments

25. Using a LMHOSTS File for Name Resolution (continued)

26. Using WINS for Name Resolution
Each NetBIOS name is tied to a service
A WINS server is a central repository for NetBIOS name and service information
When WINS is implemented, all client computers and servers must be configured to use the WINS server

27. Using WINS for Name Resolution (continued)
WINS offers several benefits over other NetBIOS name resolution methods
Four common tasks of WINS include:
Name registration
Name renewal
Name release
Name query

28. Name Registration
When a WINS client boots up, it performs a name registration
Name registration places NetBIOS information about the client into the WINS database
It is a two-packet process
The first packet is a name registration request
The second packet is a name registration response

29. Name Registration (continued)

30. Name Renewal Each NetBIOS name registration is assigned a TTL
When the TTL is half completed, the WINS client attempts to refresh the registration
Name renewal is a two-packet process
The first packet is a name refresh request
The second packet is a name refresh response

31. Name Renewal (continued)

32. Name Release
When a computer is properly shut down, it contacts the WINS server and releases its NetBIOS name
The first packet in the release process is a name release request
The second packet in the process is a name release response

33. Name Release (continued)

34. Name Query
A name query is used to resolve a NetBIOS name to an IP address
The first packet in the name query process is a name query request
The second packet is a name query response
The response is either the IP address or a message indicating that the address could not be resolved

35. Name Query (continued)

36. Troubleshooting Name Resolution
Failure of name resolution will prevent users from connecting to resources on the network
Determine whether there are any TCP/IP connectivity problems
Check the HOSTS file and DNS settings if host name resolution is failing
If NetBIOS resolution fails, check the NetBIOS name, TCP/IP settings, and LMHOSTS file

37. Summary
Host names are used by WinSock applications to access network resources
NetBIOS names are used by NetBIOS applications
The Internet uses FQDNs to refer to resources
Host name resolution is performed in four steps
Forward lookup resolves host names to IP addresses
Reverse lookup resolves an IP address to a host name

38. Summary (continued)
A recursive lookup is performed when a local DNS server queries the root servers on the Internet on behalf of a DNS client
Common DNS record types include: A, MX, CNAME, NS, SOA, SRV, AAAA, and PTR
The NSLOOKUP utility can verify that a DNS server is configured with the proper records
The resolution of NetBIOS names to IP addresses is critical for pre-Windows 2000 clients

39. Summary (continued)
There are four ways a NetBIOS name can be resolved: NetBIOS name cache, WINS, broadcast, and LMHOSTS file
NetBIOS node types may be used to alter the type and order of NetBIOS name resolution
Broadcast name resolution is not suitable for large networks because it doesn’t work across routers
An LMHOSTS file is not suitable for large networks because the file needs to be copied to every server and workstation

40. Summary (continued)
A WINS server is a central repository for resolving NetBIOS names and offers several benefits over other NetBIOS name resolution methods
Four common tasks are performed by a WINS server: name registration, name renewal, name releasing, and name querying
When a name is registered with a WINS server, the client is assigned a TTL
If the name is not renewed by the end of the TTL, the client stops using the name