network problem

[JoeHill]

James Knott wrote: 

> Thomas Milne wrote:
> > On Wed, Apr 8, 2009 at 1:16 AM, Jamon Camisso <jamon.camisso-H217xnMUJC0sA/PxXw9srA at public.gmane.org>
> > wrote: 
> >> So I've run into a really strange network problem. Box X had IP Y. IP Y was
> >> moved to box Z. Box X and Z are behind the same switch, and use the same
> >> gateway. The switch is a 3Com 4400.
> >>
> >> The IP is accessible by any host behind the switch. But it only routes
> >> properly when on box X. Box Z, no luck. I've tested iptables on box Z, and
> >> disabled it just to be sure, no luck. Box Z also works with all the other
> >> IPs it has assigned to it, that are on the same subnet as IP Y.
> >>
> >> I'm thinking it is an arp cache on the switch or router, but don't have
> >> access to either to check. You can see where I'm going, how can I get box Z
> >> to be accessible? Arp?
> >>
> >>       
> > Don't just move the IP from X to Z, move the network card as well.
> >     
> 
> Why should it be necessary to move the NIC?  I've often moved IP
> addresses, without changing cards.

I would hope so! I certainly don't replace a NIC every time I change IP's.

> And, with lots of equipment, there's
> no card to move.  Also, the contents of an arp cache are temporay. . 

They're _supposed_ to be temporary, yes. However, try a search on 'arp cache
won't clear'. Admittedly, most of the results seem to be Windows related...

> They should clear out automagically after a few minutes.  A reboot would
> certainly flush any cache entries.

Yes, if he could reboot the machine with the arp cache. Jamon said he could not
access the router or switch.

-- 
J
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists