Re: [gentoo-user] Strange network behaviour: NIC goes down, DHCP lease renewal fails

[Mick]

On Thursday 05 Mar 2015 21:46:12 Marc Joliet wrote:
> Am Thu, 5 Mar 2015 21:19:46 +0000
> schrieb Mick <michaelkintzios@×××××.com>:
> > On Thursday 05 Mar 2015 18:33:23 Todd Goodman wrote:

> > > Is this a WiFi NIC?
> > >
> > > Is it possible the device is powering down?
> > >
> > > I've had lots of problems with WiFi devices powering down (both driver
> > > issues as well as just trying to disable the default setting of
> > > powering down.)
> > >
> > > Todd
> >
> > If not a WiFi, have you also tried to mirror a port at the router where
> > the DHCP server is running and sniff packets there?  Does the router see
> > the DHCPREQ coming through from the client PCs?
>
> They apparently don't even reach the managed switch, which is what the PC
> is directly connected to (but again: the third affected PC is on a
> different switch).  I find this very confusing :-/ (and so does our local
> sysadmin, or so I'm told).
>
> (I have to mention that the best I can do is relay ideas here to my boss
> and the aforementioned sysadmin, as I don't have access to any of the
> network hardware and software, save for the affected PCs.  I am mostly
> trying to collect ideas.)

If the router does not see the dhcp request frames coming from the PCs then 
the problem won't be with the router.  Check that the NIC on the affected PCs 
is not trying to save power by shutting down, whether this is wired or 
wireless.  As Alan said you'll need to pass some driver parameter to the NIC, 
I usually do this via the /etc/conf.d/modules file, or by adding a .conf file 
in /etc/modprobe.d/

Besides the latest drivers, also check that you are using the latest firmware 
for the NIC if it uses any and check the logs after increasing verbosity on 
the driver to make sure it loads without errors.

-- 
Regards,
Mick