The WSALookupServiceBegin query uses SVCID_INET_HOSTNAMEBYADDR as the service class GUID. The host address is supplied in lpszServiceInstanceName as a dotted internet string (e.g. "192.9.200.120"). The WS2_32.DLL specifies LUP_RETURN_BLOB and the NSP places a hostent struct in the blob (using offsets instead of pointers as described above). NSPs should honor these other LUP_RETURN_* flags as well:
LUP_RETURN_NAME | return the h_name field from hostent struct in lpszServiceInstanceName. |
LUP_RETURN_ADDR | return addressing info from hostent in CSADDR_INFO structs, port information is defaulted to zero. |