gethostbyaddr()

да, но там просто видно, что в отсутствие DNS резолвинг идет по NetBios, в т.ч. броадкастом. Естественно, от вида узла зависит. Практика это подтверждает.

MSDN
Name and Address Resolution
Windows Sockets applications generally use the gethostbyname( ) function to resolve a host name to an IP address. By default, the gethostbyname( ) function uses the following name lookup sequence:

1. Check to see if the requested name matches the hosts host name.

2. Check the hosts file for a matching name entry.

3. If a DNS server is configured, query it.

4. If no match is found, try the NetBIOS name resolution sequence described in "NetBIOS Over TCP/IP" later in this chapter, up until the point at which DNS resolution is attempted.




тут