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Re: ping -b => DUP !



Hi,

Lars Viklund a écrit:
On Wed, 2004-06-30 at 19:52, girerd wrote:
  
ping -b 172.16.5.255
WARNING: pinging broadcast address
    

First, exactly what are you trying to accomplish? Note that in general
you should not assume that all boxes will answer a "ping" to the
broadcast address. It is allowed to drop such ICMP Echo Requests,
although Linux-based systems does answer.

We had four devices (with MCM) connected on the network and we just use ping -b to verify the
IP address of each of them. And we discovered that it make them unreachable.

Note the addresses below:

  
PING 172.16.5.255 (172.16.5.255) from 172.16.4.1 : 56(84) bytes of
data.
Warning: time of day goes back, taking countermeasures.
64 bytes from 172.16.4.1: icmp_seq=0 ttl=255 time=88 usec
64 bytes from 172.16.4.241: icmp_seq=0 ttl=64 time=591 usec (DUP!)
    
                ^^^^^^^^^^^^

  
ifconfig
eth0      Link encap:Ethernet  HWaddr 00:40:8C:00:00:C3  
          inet addr:172.16.5.255  Bcast:172.16.255.255 
    
                      ^^^^^^^^^^^^

My guess is that you had the ipsetd daemon running on the box and the
broadcast ping caused it to change the IP address of the eth0 interface,
which is why you cannot reach it using the old address.

Which version of ipsetd are you running? (check the $Id$ tag in
apps/ipsetd/ipsetd.c) I seem to remember fixing this quite a while ago.
  

In this file I found :

$Id:  ipsetd.c, v 1.4 2001/08/06 12:09:21 bjarne Exp $

Thank you

Claude
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