[lug] Linux boxes drop off the net? Router problem?

[rm at mamma.varadinet.de]

On Tue, Feb 06, 2001 at 01:55:47PM -0700, Sebastian Sobolewski wrote:
[... schnipp ..]
>          But that should have an effect on both sides of the connection 
> should it not?  Ie: not being able to ping out from the machine in question 
> as well as ping in.  He seems to only have the problem of the machine 
> disappearing from the network externally. (Not being able to ping the 
> machine from another one, but he can ping from that "invisible" machine to 
> anything else) Also after the ping the machine becomes visible again to the 
> external net.  This would indicate that the configuration problem is at the 
> 3com switch.  Right?

Yes, the switch might have a wrong arp entry for the Linux' IP address.
When he 'pings' from the Linux box, the router receives a packet with
the correct hardware address of the Linux box, updates it's cache and
everything works fine again. It _might_ be usefull to keep an eye
on the arp traffic in this network (ethereal can help you quite a bit,
have tcpdump run on the box for a day or two with the appropriate filters
and open the dump file with ethereal):

>          I'm curious to see what the cause and solution to this problem is 
> as well.

Me too :-)

 Ralf