Win32 gethostbyaddr() does NetBIOS query?

Christopher R. Hertel crh at
Mon Jan 24 03:00:42 GMT 2005 which you meant that the Windows system will attempt a NetBIOS Node 
Status Query (sent to port UDP/137) if reverse DNS lookup fails.  Yes?

Known behavior.  Windows systems (the older ones, at least) tend to ignore 
the distinction between the NBT (NetBIOS over TCP) namespace and the DNS 

Does that help?

Chris -)-----

On Mon, Jan 24, 2005 at 01:04:51AM +0100, Walter H. wrote:
> Hi,
> I found a quite suspicious way the gethostbyaddr() works;
> I have a programme which calls this API for IP-addresses it gets from my
> firewall, and
> if this IP-addr has no reverse DNS entry anywhere it wants to access the
> host, but this is blocked on the firewall; if this IP-addr has a reverse
> DNS entry anywhere everything goes fine.
> this phenomena I saw on both: WinNT 3.51 with SP5a and WinNT 4.00 with
> SP6a
> Greetings,
> Walter

"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
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