nmbd & netbios name -> many addreses
Luke Kenneth Casson Leighton
lkcl at switchboard.net
Fri Mar 12 01:08:48 GMT 1999
On Fri, 12 Mar 1999, Christopher R. Hertel wrote:
> > Christopher R. Hertel wrote:
> > > It makes sense that a multi-homed host would register multiple IPs per
> > > unique name. The name represents a service, and NetBIOS is only being
> > > emulated over TCP/IP. So, the Service exists on multiple emulated
> > > NetBIOS networks, all sharing a single WINS server. Uhhhrrgh.
> > Yup: the semantic gap is rather gaping here (:-))
> > However, if the client makes the PC assumption that
> > it's on a single LAN, and that it only could have one
> > address, it's only going to try registering what it
> > thinks is it's primary address.
> The line between the NetBIOS LAN and the TCP/IP network(s) is easy to
why? both are independent transports: one is proxied over the other.
> The RFCs describe a means of emulating
> a NetBIOS LAN (emphasize LAN) over
> TCP/IP. The emulated LAN exists over the union of the IP Broadcast
> domain and the set of systems sharing the same NBNS.
> NetBIOS itself doesn't know or need to know anything about multiple
> interfaces. The IP layer handles that. The NetBIOS layer only knows (and
> only needs to know) about the NetBIOS names (i.e., NetBIOS services and
> clients) it can reach.
and because of this you can have multiple NetBIOS services and NetBIOS
clients running on *any* host *including* the same host (with any
arbitrary number of ip addresses on each and every host involved, as long
as they run tcp/ip AND they run NetBIOS over tcp/ip).
> > A very smart smb server, knowing it was on a multihosted machine,
> > might arrange to register itself with an equivalently smart wins
> > server on multiple interfaces, so we might arrange to support but
> > not require such behavior, and plan on making Samba smarter...
> The real key when it comes to multi-homed hosts is routing. If you have
> an SMB server which is multi-homed, you want your clients to get the IP
> address of the server interface which is "closest" (in hops and cost) to
broken clients (e.g wfwg) are supposed to be capable of taking _just_ the
first name in a multi-homed response and ignoring all other ip addresses.
which is why the sort is required: to minimise routing.
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