Re: Managing two ethernet connections on one ethernet port (NEWBIE)

[Dan Williams <dcbw redhat com>]

On Sat, 2009-07-04 at 23:35 +0530, Shriramana Sharma wrote:
> Hello. I am a newbie to Network Manager though not necessarily to Linux 
> and networking in general. I also use KDE 4.
> 
> My computer has only one ethernet port. I have to use the same port for 
> connecting to my ADSL modem, and the same port for connecting a 
> crossover cable for peer-to-peer file transfer using NFS between my 
> laptop and desktop. I obviously cannot do both at the same time.
> 
> What I am doing to manage both WITHOUT Network Manager is I have the 
> following files:
> 
> /etc/network/interfaces.crossover
> /etc/network/interfaces.net
> /etc/resolv.conf.crossover
> /etc/resolv.conf.net
> 
> and using scripts called switch-to-net and switch-to-crossover placed in 
> my /usr/local/bin directory to ifdown eth0, create following symlinks to 
> the appropriate file:
> 
> /etc/network/interfaces
> /etc/resolv.conf
> 
> and then ifup eth0.
> 
> Please tell me if I can handle such two connections easily with Network 
> Manager without all these symlink businesses and how to do so. Please 
> give me instructions for doing it using KDE 4 NM applet or using command 
> line. As I do not use GNOME and do not want to shift to it just for 
> using NM, I would like to do it using KDE or CLI only, not the GNOME 
> applet. (No offence to GNOME fans.)

I don't offhand know how the KDE 4 bits do it, but NM is certainly
capable of this configuration.  What you'd do is make each connection
*not* autoconnect, then you can manually switch between them.  Or, make
your preferred connection autoconnect, and make the link-local crossover
connection autoconnect=false, and just manually choose it when you
connect the crossover bits.

Beyond that, it should simply  be a matter of setting the right IP
settings (DHCP for ADSL connection, Link-Local or static for the
crossover connection).

Dan