Managing two ethernet connections on one ethernet port (NEWBIE)

[Shriramana Sharma <samjnaa gmail com>]

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.)

Shriramana Sharma.