Resolving a Name to an IP Address
If the destination to be reached by an application is in the format of a NetBIOS name or host name, then name resolution is required before IP can send the first packet. IP only understands IP addresses; host and NetBIOS names are each resolved to an IP address in different ways.
Resolving a NetBIOS Name to an IP Address
NetBIOS names can be directly resolved to an IP address through four mechanisms: consulting the cache, broadcasting, checking the LMHOSTS file or querying a WINS server. The order in which Windows 2000 uses these mechanisms depends upon the node type of the client.
Windows 2000 always begins by checking the host computer's internal NetBIOS name cache. If this fails to provide an IP address, the NetBIOS name can be resolved to an IP address using a broadcast, an LMHOST file, or a WINS servers. Which of these three is used first by any particular computer depends on its node type; the default node type is hybrid or H-node, which starts by querying a WINS server, then attempts a local broadcast to resolve the name. For a detailed discussion of node types, see "Windows 2000 TCP/IP" in this book. If these mechanisms are exhausted, a client queries its Host file, and failing that, queries its DNS server if it is configured to use one.
Note that if the only problem is NetBIOS name resolution, the computershould still be able to reach the remote resource by IP address. The tools used to diagnose NetBIOS name resolution problems are Nbtstat, Nslookup, and the net use command.
For more information about WINS, see "Windows Internet Name Service" in this book.
Resolving a Host or Domain Name to an IP Address
Host names can be directly resolved by the Hosts file or by a DNS server. Problems here usually involve a misconfigured Hosts file or DNS server, a misspelled Hosts file entry or IP address, or multiple entries for a single host in a Hosts file. The tools used to diagnose host or domain resolution problems are Nslookup or Netdiag.