My modem/router doesn't like Ubuntu

Aart Koelewijn aart at mtack.xs4all.nl
Sat Dec 13 15:56:12 GMT 2008


On Fri, 12 Dec 2008 17:17:10 +0100, Óscar Fuentes wrote:

> My internet access consists on a Xavi 7768 ADSL modem/router. It is
> connected by wire to two windows machines and a Kubuntu 8.10. After some
> hours or days, internet access on the Kubuntu machine becomes flaky,
> most connection attempts takes a long time or timeouts. The Windows
> machines have no problem. The Kubuntu machine can connect to the other
> machines on the local network at full speed, though, so the problem is
> limited to connections to/from internet.
> 
> Tried disabling ipv6 on Kubuntu, no effect.
> 
> It is not a DNS problem: pinging by IP address with the -n option is
> slow too. The most strange thing is that ping seems to hang for several
> seconds: it doesn't react to Control-C immediately. The reported times
> (when ping obtains a response) are on the range of milleconds, when ping
> takes several seconds (typically 10 or more) to report responses. With
> `dig' I see something similar: it seems to hang for several seconds and
> then either reports a timeout or says that the response took a few
> milliseconds.
> 
> The only cure for this is to restart the router. Then internet works for
> the Kubuntu machine for some hours or a few days until the problem
> appears again.
> 
> If this is a problem with the modem/router, is there some setting I
> could try to avoid it?

It could be a problem with the NAT tables in the router. It might help if 
you run a caching nameserver (named/bind) in your Linux box.

Aart





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