SAMBA Browse Lists Sync DMB and LMB

Alex H. Vandenham alex at
Fri Apr 21 13:01:55 GMT 2000

I have been working on a similar and related problem (details below).  The cause
of this behaviour is simply the way the SMB protocol was designed - it's part of
NetBIOS and samba just copies that behaviour.  Here's what happens;

When a new host boots on the LAN, it sends an announcement to the Local Master
Browser (LMB) .  The announcement is repeated, frequently at first, but settles
down to once every 12 minutes.  If the host is then turned off, the LMB waits
for 3 announcement cycles (36 minutes) before removing the host from the browse

When a host becomes an LMB, it sends out an announcement to the domain master
browser every minute for 5 minutes and then repeats the announcement every 15
minutes.  If those announcements stop, a LMB or DMB will wait for 3 cycles (45
minutes) before removing the host from the browse list.  

You can see that in some cases, (when the browse lists have to be
synchronised between LMB/DMB on different subnets) it could take as long as
(almost) 1.5 hours between the time that a host is removed and the time that
all the browse lists are updated.   

The consequence to this behaviour is that browsing the host will fail
with a message from Windows saying that the computer is not available.  

If you would like to see some other "strange" behaviour, go to one of the
windows PCs, edit network properties and change the workgroup name to something
different.  Reboot and wait for the change to propagate through the browse
lists.  Note that the only correct browse list is on the PC that you changed. 
Every other browse list will be wrong.  Now go back and change the workgroup
name back to the correct name.  Let me know if you figure out how long it takes
for that change to disappear from the browse lists.

For some details, look at nmbd_winsserver.c lines 727-744 (2.0.6).  Does anyone
know why samba does NOT register the IP address of the LMB when recording the
workgroup in the wins database?  It's causing problems for our network.

Alex Vandenham
Avantel Systems

On April 21, You wrote;

Hello !

  I have a problem of syncing browse lists between 
DMB and LMB.

  The topology of ours network is as follows:

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