[olug] Ethernet connection

[Rob Townley]

On Wed, Apr 21, 2010 at 9:16 AM, T. J. Brumfield <enderandrew at gmail.com> wrote:
> Welcome to the list!
>
> What I've seen happen from time to time is that when you take a computer
> from one environment to the next, Networkmanager doesn't always correctly
> set /etc/resolv.conf which has the DNS settings.
>
> You can open up a console and try ifconfig to see your NIC settings. You can
> then try to ping the ip address of your router/cable modem/whatever at home.
> You can also try pinging a known ip address like 8.8.8.8 (Google's public
> DNS server).
>
> If you can reach that, your NIC is working, but DNS is not. You may want to
> look at /etc/resolv.conf
>
> There isn't any reason I can imagine that your NIC driver and such works in
> one environment and not the other.
>
> -- T. J. Brumfield
>
> On Wed, Apr 21, 2010 at 9:02 AM, <jonsteckelberg at cox.net> wrote:
>
>> Greetings,
>>
>> This is my first post on this mailing list. I have a problem with my wired
>> ethernet connection.
>> I have a Thinkpad X31 running openSUSE 11.2 KDE.  Actually I am having
>> problems with both the wireless and the wired connection but I want to focus
>> on the wired at the moment. The problem is that when I connect to the wired
>> network at work everything is fine it connects automagically and I have
>> internet access but when I plug into my home network it does not connect.
>>  It seems like it can not find the network address.
>> More info;
>> Thinkpad x31
>> open SUSE 11.2 KDE
>> knetwork manager
>> Home: Cox internet
>> Router: Netgear WGR614
>> other computers on home network that work just fine
>> 2 PC's runnin Linux Mint
>> 1 PC runin XP (sorry wifes computer)
>>
>> Can anyone provide me some assistance?
>> If you need more info to help solve problem let me know.
>>
>> Thanks
>> Jon Steckelberg
>> _______________________________________________
>> OLUG mailing list
>> OLUG at olug.org
>> https://lists.olug.org/mailman/listinfo/olug
>>
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>

Worse would be when the dhclient part of NetworkManager misses
something else besides DNS such as the default gateway.  Can you ping
other hosts on your lan, but not get out of the lan.

#cat /etc/resolv.conf
#ifconfig -a
#ip address
#route
#ip route show

Compare IP subnet and default gateway to a working machine.
If it is different, force the dhcp client to renew:
#dhclient eth0

Stop all networking and restart
#/etc/init.d/NetworkManager stop
#/etc/init.d/network stop   (i am assuming this is on suse)
#/etc/init.d/netplug stop   (you may not have this running which is ok)

Change stop to start above.

If dhclient / NetworkManager still isn't giving you the right numbers,
then it is worth to hunt down any old dhclient related *.lease files
on your system.  Especially, if at one time, the dhcp server was set
to hand out leases for a very long time.  On a Fedora 11 system, dhcp
lease files are stored in /var/lib/dhclient/, so do a #find / -name
dhc.  Normally, it does not hurt to erase all these files but you may
want to mv them somewhere under /tmp/oldleases/ in case work does
something like TLS 802.1x.   You might notice that your home network
lease has old values for option routers, ns, domain-name, but it has
not expired yet.

cat /var/lib/dhclient/dhclient-long-ugly-GUID-wlan0.lease
lease {
  interface "wlan0";
  fixed-address 192.168.168.230;
  option subnet-mask 255.255.255.0;
  option dhcp-lease-time 86400;
  option routers 192.168.168.1;
  option dhcp-message-type 5;
  option dhcp-server-identifier 192.168.168.1;
  option domain-name-servers 192.168.168.1;
  option dhcp-renewal-time 43200;
  option dhcp-rebinding-time 75600;
  option domain-name "lan";
  renew 5 2009/12/25 02:50:46;
  rebind 5 2009/12/25 13:47:45;
  expire 5 2009/12/25 16:47:45;
}

Once these are cleared out, you will probably never have a problem again.

If your stuck at home, give me a call 402-522-6266.  i promise i don't
usually talk as much as i write, but i had a compulsion to do a brain
dump....just now.