Browsing Elections and the 'os level' parameter

Jay Ts jay at
Fri Feb 15 19:42:02 GMT 2002

Hi Everyone,

I'm working on the chapter in O'Reilly's Using Samba, 2nd ed.
that covers browsing and browsing elections.  In the first
edition, the original author listed some inaccurate information
in the table on Windows OS Type values, and I want to correct that.

First I looked through the Samba textdocs and htmldocs, then
dug up everything I could on the Microsoft site, which amounted
to 2 white papers.  Those two papers had contradictory information,
and the Samba docs weren't of much help, even when documenting
the "os level" parameter.  (For example, some of the docs use
an os level of 65 to force Samba to be the master browser,
without explaining why this specific number is used, and in
BROWSING.txt it says the maximum os level is 255.  Wouldn't
it be better to just use 255 to really make sure?)

So I have spent the past day running ethereal here, with various
combinations of Windows and Samba PDCs and workstations.  I've
found what Windows systems use as the OS Type value (os level, in
Samba smb.conf terms), and I'm hoping y'all can take a look
at this and let me know if I'm off anywhere, or missing anything:

Operating System and Configuration	OS Type value
(MS-DOS or Win 3.x, with Microsoft	?
	Network Client installed)
(Windows for Workgroups)		1
Windows 95				1
Windows 98				1
Windows Me				1
(Windows NT 3.x Workstation)		16
(Windows NT 3.x Server, member server)	16
(Windows NT 3.x Server, as PDC)		32
(Windows NT 4 Workstation)		16
Windows NT 4 Server, as member server	16
Windows NT 4 Server, as PDC		32
Windows 2K Professional			16
Windows 2K Adv.Server, as member server	16
Windows 2K Adv.Server, as NT-PDC	32
(Windows XP Home)			16
Windows XP Professional			16

The OS versions in parenthesis are versions I don't have,
and can't test, and the OS Type values are either taken from
documentation or (more likely ;) assumed.  Do they look right?

One thing to go along with this: it seems that Windows and
Samba both compare the OS Type values as integers rather than
bits, so an "os level" of 33 for Samba will beat a Windows
system having an OS Type of 32, even though ethereal reports an
value of 33 as a system that is both Windows NT Server and
Windows for Workgroups (i.e., 32 anded with 1).  In other words,
it is not necessary to use the next bit over (64, or even 65 ;)
to win against any Windows PDC.

I think it would be a good idea to get the OS Type values clear
and document them so that the users will know exactly how to
get Samba to beat or lose elections against specific Windows

Comments appreciated!

Jay Ts
jayts at

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