[ILUG] intermittent IP failure

[paul at clubi.ie]

On Wed, 4 Jun 2008, Kae Verens wrote:

>  I would suspect the router connected to the machine, except that 
> that wouldn't explain why resetting the IP settings brings it back 
> up.

If you run a script on the host to ping the router every minute or 
so, does that fix things?

As Ken pointed out, your default gateway is not on the same IP 
subnet.

My guess: this works as long as the host initiates communication - 
its routing table has the IP of the router, and it's on-link, so ARP 
works - which is enough to get an entry in the ARP table of the 
router and allow 2-way communication. The randomness is explained by 
patterns of communication between your host and the router. I'm 
guessing that, when its the router that initiates and it has no ARP 
entry for the host, that it's sending the packets back to its default 
route. (Traceroute from outside shows loops?).

If that's the case, you can fix the problem by adding a route (either 
for your host or the additional IPs) on the router - presuming it 
lets you configure routes targetting just an output interface..

Alternatively, put the router on the same IP subnet...

regards,
-- 
Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
Fortune:
Jupiter is aligned with Mars.