Browsing Elections and the 'os level' parameter

Richard Sharpe sharpe at
Fri Feb 15 19:59:02 GMT 2002

Jay Ts wrote:

>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

These are the values I recall seeing, and this makes sense according to 
the browsing docs that MS provided that I saw. I think some of this is 
in the CIFS doc now.

Of course, since I originally wrote the code in Ethereal that dissected 
these things, you might want to use another monitor tool to cross check :-)

>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

Richard Sharpe, rsharpe at, rsharpe at, sharpe at,, SAMS Teach Yourself Samba 
in 24 Hours, Special Edition, Using Samba

More information about the samba-technical mailing list