DC's name / server mutex ??

Jeremy Allison jra at samba.org
Fri Jul 16 16:46:59 GMT 2004

On Fri, Jul 16, 2004 at 06:40:45PM +0200, Volker.Lendecke at SerNet.DE wrote:
> Hi!
> During attempts to optimize our connection attempts to domain controllers I
> wondered why we take such a huge effort to find the DC's name.  My impression
> is that this is only to be able to grab the server mutex by name. This
> implementation can be called a bug itself. Even when connecting to the DC via
> Kerberos we get the server's principal name in the negprot reply.
> We do need the mutex, but why on the name? Isn't the IP address enough? Then a
> much simpler implementation would be possible: Simply fcntl lock one byte in
> the 2^32 space of IP addresses. Even on systems with only 2^31 fcntl lock space
> we could do it with two lock files.
> Given that it should be a lot simpler to find a DC to connect to. For our own
> domain do either dns svr record lookup, or lookup on #1C. On port 139 all DC's
> should be able to listen on *smbserver, so even there I don't see a reason to
> risk a timeout.
> Where am I wrong???

As I recall the effort to find the name is for NT4.x DC's which require
a correct NetBIOS name in the initial NetBIOS session request. If we
can really junk this (ie. *SMBSERVER always works) then yes the IP address is enough.


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