IP address clash under Linux on LAN

dazdaz · 10-10-2005, 03:53 AM

What happens when the same IP address is configured on 2 different Linux boxes on a LAN.

And what happens to the router. Does it send the packets to both hosts or none. Or the last host or the first...

Does the Linux kernel detect this ? Is anything recorded into /var/log/messages ?

I think arp/rarp comes into play here, but I don't know exactly how.

Thanks.

Agrouf · 10-10-2005, 04:15 AM

I didn't test, but I'd say that it depends on the router implementation.
The router will send arp request and receive 2 arp responses.
So my useless answer is :
Either it sticks to the first one received or it overlaps it with the 2nd one, or it puts 2 entries in the arp tables, or it discards both as invalid.