Mailslots over UDP
Many NetBIOS applications use mailslot messaging. A second-class mailslot is a simple mechanism for sending a message from one NetBIOS name to another over UDP. Mailslot messages can be broadcast on a subnet or directed to the remote host. To direct a mailslot message to another host, there must be some method of NetBIOS name resolution available. Microsoft provides Windows Internet Name Server (WINS) for this purpose.
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