Browsing across subnets without WINS

Christopher R. Hertel crh at ubiqx.mn.org
Tue Mar 18 17:51:06 GMT 2003


On Tue, Mar 18, 2003 at 07:34:45AM -0500, David Collier-Brown -- Customer Engineering wrote:
>   Guys, is this an expected behavior? Unless you have WINS
> up (which causes issues with multihomed machines), one
> seemingly cannot synchronize browse lists across subnets.

Samba's WINS does a good job of handling multi-homed systems.
Microsoft's design for multi-homed WINS entries is ugly...but it should 
work.

More...

> --dave
> 
> Pedro Guedes wrote:
> > Browsing across subnets is well documented on the 2 main books
> > about Samba (the o´reilly one and the John D. Blair older
> > one - the first of  all).
> >
> > I usually do not use WINS, even on W2K because
> > it does not work correctly on multihomed servers.

I have heard many reports (and seen a few traces) of bugs in W2K's WINS 
implementation.

> > It binds on only one interface (the primary one if one can state
> > correctly which one it is - on 99% of the cases the one on the
> > lowest PCI slot).

Samba's WINS can be set to bind to which ever interfaces you like.

> > One can read a couple of white papers from microsoft stating
> > just that, I think this is due to the NetBIOS name coupled
> > to the machine in contrast to the name coupled to the IP
> > interface, even in the NeBT world.

NetBIOS names are assigned to services or applications.  Not to interfaces 
or devices.  That's the way NetBIOS works.

So that's right in the sense that the NetBIOS name is never bound to the 
interface.

> > What I tried to do is make samba win browse master elections
> > (in subnets away from the subnet where  the PDC resides - it
> > always wins and without any local NT4 Backup Domain Controlller
> >  or W2K Domain controller) based on the idea of  the Unix server
> > being always on-line should always take the role despite the
> > presence of W98 & W2K Professional always coming and going.

Yes, but having Samba become the *local* master browser doesn't help much.

> > The idea is to change browse lists with the domain master
> > browser (the PDC or FSMO on W2K) so that browsing accross
> > subnets works for everybody.

...but the DMB can't be contacted unless you can find the name via WINS.

> > In fact Samba becomes the master browser on the LAN due to
> > higher values on election based on the setting "os level".
> > It wins over W2K Professional (the highest Windows on the LAN).

Right.

> > But ....
> > Despite settings of  "remote announce" ,"remote browse sync",
> > entries like 192.168.5.20    ISLA#1B     in lmhosts
> > to talk to the PDC/FSMO (I known it says it only works with
> > other samba server) what the Domain Master Browser receives
> > is only the samba server itself, no neighbours listed at all.

Remote Announce sends the Samba server's announcement directly to the DMB, 
so the DMB will know about the Samba server.  That's what you are seeing.

Remote Browse Sync only works between Samba servers.

> > I have, since the early samba releases, noted this behaviour.
> >
> > So, what I do is make W2K Professional force and win browse
> > master election when it boots.
> > (look at HKLM\System\CurrentControlSet\Services\Browser\ for
> > the values
> > MaintainServerList - yes
> > IsDomaiMasterBrowser - yes
> > This way browse lists always propagate correctly to the
> > Domain Master Browser.
> >
> > This samba behaviour (or lack of it) is quite unfortunate

Samba's browsing behavior is a *superset* of Windows behavior.

> > since the W2K Professionals are always coming and going making
> > subnets browsing quite unstable.
> >
> > It is strange that the samba servers have such poor behaviour
> > despite their phenomenal growth in the integration
> > Unix/Windows arena.
>
> > A little bit more could be written about this.
> > If you have any sugestions they would be welcome.
> > This matter truly deserves an article somewhere. In O´reilly
> > web pages, on Linux/Windows Magazines.
> > Maybe a better writer than me could write a paper on it.

I am currently finishing the Browsing section of my book.  See:
  http://ubiqx.org/cifs/Browsing.html

I'll be finishing as much as I can in the next week or so.  See also:
  ftp://ftp.microsoft.com/developr/drg/CIFS/cifsbrow.txt  

...and also read the discussions of browsing parameters in the smb.conf 
manual pages.

Basically, though Samba does a good job with browsing.  Better than many 
Windows implementations.  The key thing is that synchronising complete 
browse lists with a DMB will *not* work unless the LMBs know where to find 
the DMB.  WINS is typically the way that is done.

I don't know whether adding a #1B entry to the lmhosts file will signal
Samba that it needs to browse sync with the given entry.  If Samba is not
aware of a WINS server it *may* not try to sync with any DMBs.  *This is
pure supposition on my part.*  I don't know that part of the code as well
as I should (yet).  In any case, make sure you have lmhosts name
resulotion enabled.

I *have* seen a problem with browsing between Samba and Windows systems.  
I was not able to resolve the problem at the time because it was a problem 
in a computer lab at a conference and I did not have either time or 
resources.

I think that it would help me to have a better understanding of the 
situation above.  At this point I'm just guessing...

Chris -)-----

-- 
Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org


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