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Re: Ethernet connection weirdly not working mornings



Hello,

Am 29.06.2011 07:03, schrieb John Magolske:
> Since switching to a new machine and upgrading to the latest Sid, I've
> been having some weird problems getting a wired connection to the net.
> 
> Running `ifup eth0` brings up a net connection -- but not in the
> morning for some reason....times out with a "No DHCPOFFERS received"
> message. Repeatedly. I've been trying this every day for over a week,
> and like clockwork, morning = no connection, evening = connection.
> 
> BUT, even though the ethernet connection doesn't work in the mornings,
> `ifup wlan0` will bring up a wireless connection in the morning just
> fine. This "I'm not a morning-type" ethernet is coming out of the very
> same NETGEAR wifi router that successfully provides a wifi connection
> any time of day.
> 
> And when I try my old laptop (running a not-as-up-to-date Sid), it
> works fine, gets that ethernet connection in the mornings every time.
To bring light into this issue you shut sniff your ethernet traffic,
when bringing your interface up.
This could be done using wireshark or tcpdump.

Issuing
tcpdump -i eth0 -s 0 -w <outfile>

before "ifup eth0", should give some valuable information.
You can kill tcpdump (Ctrl+C) after the DHCP timeout.

If you can't interpret the resulting capture yourself, you could post it
here.
Then we should be able to see the communication between the dhcp server
und your box.
Of course looking into the server logfile would be a good alternative to
this, but I suppose, that this isn't possible (with a reasonable amount
of effort) for a dhcp server running on a wifi router box.

Another idea: Could there be some kind of child protection running on
the wifi router preventing the access at some time interval for
specified computers?

HTH,
Enno

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