If it's "across the wire" all you're going to get is the DNS reverse lookup. Machine names are not necessarily the same as the DNS name, and all TCP/IP w/DNS will give you is just that: The DNS name, which may or not be the machine name. NetWkstaGetInfo() will only work on Windows machines (Pre Windows 2000 or Pre Windows 2000 compatible) where Anonymous access is allowed (a reeeeely reeeeeely reeely bad practice!) Why do you need to know the actual machine name anyway? If there's suspicious behavior, you can trace the IP back. If it's illegal behavior, you can go deeper and give the authorities your firewall logs for the offense.