Strategy for mapping the neighborhood

[Daniel Reed]

On 2003-10-29T15:30-0800, David Wuertele wrote:
) But P nodes do contact the DMB, and that gets merged into all LMB
) lists, right?  In any case, assuming that the LMB's don't know all the
) P hosts, one strategy to find P nodes would be to:
)
)   a.  ICMP Echo to the subnet broadcast IP to find all NICs on the LAN
)   b.  attempt an NBSTAT to each NIC

You can actually use NMB directly to perform the broadcast, as in the
command:
nmblookup \* -B 255.255.255.255

Windows hosts at least in broadcast or hybrid mode will respond, as will
Samba in every configuration I have seen.

Any sufficiently large network may have gaps in local browse lists from
dropped packets, machines being rebooted, mobile machines being removed from
the network, etc.

I think the way Celery works is exactly what Christopher R. Hertel
suggested: Send 3 (or several) broadcasts over 10 seconds, then remove
duplicates. Repeat every hour or so. Keep known hosts for 24 hours even if
they do not respond to broadcasts.

-- 
Daniel Reed <n at ml.org>	http://naim-users.org/nmlorg/	http://naim.n.ml.org/
It is so easy to miss pretty trivial solutions to problems deemed
complicated.  The goal of a scientist is to find an interesting problem,
and live off it for a while.  The goal of an engineer is to evade
interesting problems :) -- Vadim Antonov <avg at kotovnik.com> on NANOG