> Pinging a broadcast address on the local ethernet confuses arp:
> 
> ---8<------8<------8<------8<------8<------8<------8<------8<------8<---
> [/tmp] root@rumolt > ping -c 1 194.77.123.128
> PING 194.77.123.128 (194.77.123.128): 56 data bytes
> 64 bytes from 194.77.123.129: icmp_seq=0 ttl=255 time=1.209 ms
> 
> --- 194.77.123.128 ping statistics ---
> 1 packets transmitted, 1 packets received, 0% packet loss
> round-trip min/avg/max = 1.209/1.209/1.209 ms
> [/tmp] root@rumolt > ping -c 1 194.77.123.143
> PING 194.77.123.143 (194.77.123.143): 56 data bytes
> 64 bytes from 194.77.123.129: icmp_seq=0 ttl=255 time=1.030 ms
> 
> --- 194.77.123.143 ping statistics ---
> 1 packets transmitted, 1 packets received, 0% packet loss
> round-trip min/avg/max = 1.030/1.030/1.030 ms
> [/tmp] root@rumolt > arp -a
> ? (194.77.123.128) at (incomplete)
> ? (194.77.123.143) at (incomplete)
> [/tmp] root@rumolt > ifconfig ed0
> ed0: flags=9863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,LINK0,MULTICAST>
>         inet 194.77.123.129 netmask 0xfffffff0 broadcast 194.77.123.143
> ---8<------8<------8<------8<------8<------8<------8<------8<------8<---
> 
> This doesn't hurt, but at least looks ugly ;-)
> I would call it a bug. Does it make sense to enter this types of addresses
> (which could never be assigned to a correctly configured device) into the
> arp cache?
> 
> The same things happen with standard class C networks, so its not a question
> of my unusual (is it?) netmask/broadcast address.


I think it is normal, my 1.2 and BSD/OS does it too. "(incomplete)" means
only link info without ethernet address is available, which is fine (outgoing
interface is computed for broadcast address).

-- 
Zdenek Salvet                                              salvet@ics.muni.cz 
----------------------------------------------------------------------------
           If God had meant for us to be in the Army,
         we would have been born with green, baggy skin.