When I start Antix 15 the new ethernet that I'm using connects to the internet. I do not know what I am doing with Antix 15; so I figured it would be better to ask here how I can temporarily disconnect the ethernet without changing its automatic connection at start up!! Thanks!!

the easiest way is from a teteminal to use

sudo ifdown eth0


to bring it back up use

sudo if up eth0

Thanks Dolphin!!