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There are 2 common types of name resolution; DNS host names (used by winsock and sockets apps like ping, telnet, and SMTP/POP mail) and NetBIOS names (used my most MS network functions such as browsing and mapping drives). For each of these, there are a number of possible variations in the resolution sequence, depending on your system setup. Assuming you have all options available and the node type is hybrid (h-node), the sequences are:

(Note. The first test, in both cases, is to see if the name is the local machine.)

Note 1. W2k adds a 'DNS cache' to the resolution order. DNS cache is checked just before the local hosts file.

Note 2. If you have WINS and/or DNS entries specified, but the servers are unavailable, you will experience delays as the systems tries several times to reach each server before falling through to the next method.

Note 3. Each DNS server in the list will be queried, one by one, until either a definitive answer is received (either a resolved name or a authoritative No). If an authoritative No is received, resolution will fall through the next resolution method or fail, if no other method is available. This behavior was changed somewhat in NT 4.0 SP4 (KB article Q198550), but I have yet to find a detailed description of the new behavior.

Note 4. On all current WINS clients (NT 3.51, NT 4, 95, 98, WFW with TCP/IP 3.11b), if the Primary WINS server is unable to resolve a name, the Secondary WINS server will be queried.

Note 5. When attempting a NetBIOS connection, if the name is more than 15 characters (NetBIOS names are limited to 15 characters) in length or contains a dot (.), it will be treated as a DNS name.

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