In article <199508071236.IAA04356@panix2.panix.com>,
John Hawkinson  <jhawk@panix.com> wrote:
> > From: christos@deshaw.com (Christos Zoulas)
> 
> > >[lola-granola!jhawk] ~>  ping 0
> > >PING 0 (0.0.0.0): 56 data bytes
> > >64 bytes from 18.70.0.1: icmp_seq=0 ttl=255 time=1.466 ms
> > >
> > >(18.70.0.1 is the default router).
> > 
> > 18.70.0.1 is a cisco I bet... Nothing else answers on our network, but
> > a cisco 2 hops away... And we have a lot of different fruit flavors
> > in our garden...
> 
> Well, yes, but nothing else even has a _chance_ of answering. To a
> tcpdump -e -- the packets are sent off to your default router, which
> will either answer, forward to its default, or drop.

Yep... with no default router on a sun, ping 0 bails with "Network is
unreachable". 

BTW, another interesting excersize is to ping the broadcast address...
With StunOS 4.1 I get three replies (== number of booted hosts on the
local net at this moment), all with the local IF address:

PING XXX.XXX.XXX.255: 56 data bytes
64 bytes from foo.bar.com (XXX.XXX.XXX.5): icmp_seq=0. time=20. ms
64 bytes from foo.bar.com (XXX.XXX.XXX.5): icmp_seq=0. time=40. ms
64 bytes from foo.bar.com (XXX.XXX.XXX.5): icmp_seq=0. time=60. ms

----XXX.XXX.XXX.255 PING Statistics----
1 packets transmitted, 3 packets received, -200% packet loss
round-trip (ms)  min/avg/max = 20/40/60

On AS225 B2R5 I get one reply per host as well, but with different
addresses. Replies from other hosts have their addresses, the local
reply has the broadcast address:

PING XXX.XXX.XXX.255: 64 data bytes
64 bytes from XXX.XXX.XXX.5: icmp_seq=0. time=10.42 ms
64 bytes from XXX.XXX.XXX.255: icmp_seq=0. time=1013.75 ms
64 bytes from XXX.XXX.XXX.2: icmp_seq=0. time=2014.41 ms

----XXX.XXX.XXX.255 PING Statistics----
3 packets transmitted, 3 packets received, 0% packet loss
round-trip (ms)  min/avg/max = 10.42/-986.91/2014.41

Note that the statistics are different and wierder.

Just turned on a PC with NCSA telnet, and results are the same... it
does not reply to broadcast pings, though it does reply to direct pings.
I don't have a ping client for it.

Booting WfWG 3.11 with TCP32 on it, it behaves the same and does not
answer broadcast pings.  Running ping, it gets only one reply per ping,
and lists the broadcast address.

The ESIX SVR4 machine we had used to do something odd, but I forget
what.

Dunno if I ever tried it on NetBSD, but I can't at the moment.

Anyway, I don't know what any of this means, but it's interesting
(well... maybe that's too strong a word :->) how variegated handling of
broadcast pings is. No two systems seem to handle it quite the same, and
none does quite what I'd expect.

-- 
Ty Sarna                "I guess one person _can_ make a difference,
tsarna@endicor.com       but usually they shouldn't" -- Marge Simpson