[CentOS] Neighbour table overflow

tdukes at sc.rr.com tdukes at sc.rr.com
Fri Nov 28 16:00:11 UTC 2008


---- Robert Moskowitz <rgm at htt-consult.com> wrote: 
> Thomas Dukes wrote:
> >  
> >
> > *From:* centos-bounces at centos.org [mailto:centos-bounces at centos.org] 
> > *On Behalf Of *chloe K
> > *Sent:* Thursday, November 27, 2008 9:10 PM
> > *To:* CentOS mailing list
> > *Subject:* Re: [CentOS] Neighbour table overflow
> >
> > what is your netmask?  
> >  
> > eth0 = 255.255.240.0
> 
> Why do you have such a large subnet?  There are a number of potential 
> performance problems with such a setup.  I typically only see this in 
> large, bridged wireless campuses.  Little justification for it in a 
> wired network.  (I do have lots of networking experience and knowledge, 
> having consulted with a number of large deployments).
> 
> Even with a large subnet, you should not be arping everywhere.  Either 
> two things are happening:
> 
> Your system is recording every ARP request it sees ('Who has IP 
> x.x.x.x') to avoid arping later.  Bad behaviour (IMNSHO), given your 
> network.
> 
> Your system is ARPing for every IP address in the subnet to learn all of 
> its neighbors.  WHy would it do that?  Unless you have some snooping 
> software running on your system.
> 
Hi Robert,

I did not set this value.  Something did but not me.

I am on a roadrunner connection with a dynamic ip.  What do you suggest I change it to?

Thnaks!!


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