Two Simple Questions (Multi Home)

MCCALL,DON (HP-USA,ex1) don_mccall at
Fri Mar 16 15:46:18 GMT 2001

Hi Robin,
Certainly not in a broadcast senario; in broadcast,
the server basically sends out a 'name claim' packet
via broadcast, and if NOONE sends back a negative response
(ie, they already believe they own the name), then the 
claim succeeds.  So you can see how that would lead samba
to basically tell itself, NOPE, you can't have that netbios
name on that ip address, since I already have it on THIS ip 

I believe (but have not tested) that even with wins, you
would run into an issue, since you would be registering the 
same set of netbios names to the wins server with two different
ip addresses in the same subnet.  Think about it; when a client
also using wins goes to the wins server looking for one of these
names, WHICH ONE will the wins server give him back?  So I believe
that what is going to happen is that if we DID allow both 
interfaces to claim the names even on the same subnet, that the 
Wins server would register the 1st set with ip address 1, and then
when the next set (with ip address 2) of registrations came in,
they would REPLACE the original ones.

Bottom line is, I don't think you can get away with this.

-----Original Message-----
From: Julia Holloway [mailto:jhllwy at]
Sent: Friday, March 16, 2001 10:12 AM
Cc: samba at
Subject: RE: Two Simple Questions (Multi Home)


Thanks for the reply.   As for the netbios name collisions, if the server
is registering its name in a multihomed capacity, doesn't this take care of
name collisions??  I imagine it would with a WINS server, but perhaps not
in a broadcast scenario??

email: jhllwy at

"MCCALL,DON (HP-USA,ex1)" <don_mccall at> on 03/16/2001 09:01:28 AM

To:   Julia Holloway/Raleigh/IBM at IBMUS, samba at
Subject:  RE: Two Simple Questions (Multi Home)

Hello Julia,
On question 1&2, yes, nmbd will register it's netbios names ONLY on the
1st ip address in a subnet.  If you have additional ip addresses IN THE
SAME SUBNET, it will disgard them.  It does this because to NOT do it would
cause netbios name collisions, and name resolution issues.
And since you are on the same subnet anyway, the only load balancing that
you would accomplish is the thruput on the NICS, since the WIRE is going
to have the same traffic either way - in fact, since netbios browsing is
so 'chatty', your actual network bandwidth (on the wire) would increase if
you were able to do this.
If you are thinking that you need to do 'load balancing' you imply that
you are experiencing some sort of performance issues; you should make sure
that the NIC is really the bottleneck; not the cpu/disk resources that
samba is using based on the amount of traffic it is having to handle, or
the amount of traffic physically on the wire - perhaps you really DO need
to subnet.
Hope this helps,
-----Original Message-----
From: Julia Holloway [mailto:jhllwy at]
Sent: Thursday, March 15, 2001 5:56 PM
To: samba at
Subject: Two Simple Questions (Multi Home)

Dear Samba List,

I have been reading the archives for mention of multi-homed Samba, and
Samba over multiple subnets.  I have two questions:

1) It is true that the nmbd daemon will only allow one IP address per
subnet to be added to the local interface list?   So if I had a Linux
machine with two NIC cards connecting to the same HUB, using the same
subnet, only one of these interfaces will be used?

2) What I was hoping to do is set up my Samba server as a multi-homed
server, with multiple addresses on the same subnet.  Then I was going to
let my WINS server (or DNS for that matter) function as a simple load
balancer, so that the client requests could be spread over the different
NIC cards.   Is there anyone else that would be interested in a setup like
this, besides me??

3) On another subject,  I notice that when I allow my NT4 Server to be the
local master browser, the entry "__MSBROWSE__-[01h]" can be found in the
WINS server database.  However, if I let the Samba server become the local
master browser, there is no "__MSBROWSE__" entry.  Has anyone else noticed
this?  Is this a problem??

Julie Holloway
T/L 444 - 0056, ext  (919) 254 - 0056
IBM Storage Networking

email: jhllwy at

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