NETWORKING /etc/resolv.conf/ Ubuntu 10.0.4

[zongo saiba]

On Sat, 2010-05-15 at 15:17 -0400, Tom H wrote:
> On Sat, May 15, 2010 at 12:31 PM, zongo saiba <zongosaiba at gmail.com> wrote:
> > On Fri, 2010-05-14 at 20:49 -0400, Tom H wrote:
> >> On Fri, May 14, 2010 at 7:54 PM, Asif Iqbal <vadud3 at gmail.com> wrote:
> >> > On Fri, May 14, 2010 at 3:32 PM, zongo saiba <zongosaiba at gmail.com> wrote:
> >> >>
> >> >> Could anyone tell me why my /etc/resolv.conf/ file gets emptied and then
> >> >> I lose all connections to my wireless network ? I mean, I have figured
> >> >> out why this was happening. I have to manually reconfigure manually
> >> >> resolv.conf everytime this happens and all his back to normal.
> >> >>
> >> >> resolv.conf is controlled by NetworkManager. Should I configure
> >> >> NetworkManager in any particular way ? Or May by my routeur ?
> >> >
> >> > if you are getting ip through dhcp then just use prepend or append
> >> > your resolvers
> >> > in your system.
> >> >
> >> > man dhclient.conf or vi /etc/dhcp3/dhclient.conf to get some idea.
> >>
> >> If using NM, it is probably more appropriate to make configuration
> >> changes within NM's GUI. I don't have NM installed to check this, but
> >> it must have a field for specifying DNS servers.
> >
> > Indeed it does. I was suffering network connection loss eventhough I had
> > configured the GUI properly. Plus the Wifi connection or card (still
> > don't know) was very talkative and was filling up my logs pretty fast.
> > Plus, my resolv.conf was being whipped clean every other time which had
> > for result to cut off my connection from the router. Since I have
> > configured (as off today) dhclient.conf (as per man page) it seems to be
> > a lot better. I have just tested the connection today only, but will
> > come back on that in a couple of days with better estimate of the
> > reliability of my connection. An interesting fact here: Before actually
> > changing the dhclient.conf file, I had changed the configuration
> > in /etc/network/interfaces which had a terrible effect on my wifi
> > connection but also on NM. NM was still running in the background but
> > not showing in the menu bar at all. I could not scan wireless networks.
> > I could only connect with ifconfig and ESSID of the network which worked
> > nicely but still needed my notebook to scan for other wireless networks
> > especially when I was on the move. Nevertheless, it seems that I slowly
> > getting back to normal with my wifi connection.
> 
> Unless you change the nm_controlled variable, defining more than lo in
> /e/n/i won't work. NM will keep on running and, I think, mess with
> your DHCP (and hence your resolv.conf) settings.
> 
> If you're comfortable at the cli, editing dhclient.conf and running NM
> should give allow you to scan wifi networks and set specific dns
> servers.
> 

Which I have done and it seems that everything is working ok now. I
actually did not define more than one lo in /e/n/i but i just added some
settings for my network interface "wlan": Here are the settings I added
in /e/n/i:

auto lo
iface lo inet loopback

# Primary Network Interface
# auto wlan0
# iface wlan0 inet dhcp

That did mess up NM on two levels: 
- NM did not show on the menu bar anymore
- NM did not scan anymore for wireless. 

The part that I did not understand, is I could still connect to my
wireless network with a simple command-line with the ESSID of my
wireless network as such: 

$ sudo ifconfig wlan0 ESSID

The connection was actually a lot faster then.

Kind Regards, 

Zongo