Multiple connections, net only on one

This is hard to word. Basically I have a wifi connection, and an ethernet connection.

The wifi connection is to provide my internet.

The lan connection is using a crossover cable to connect to my ‘file server’ which also has 2 connections. It’s connections are both lan, one for web, one for sharing files directly via the crossover cable to me.

The problem is instead of the machine I want to use wifi for internet, it uses the internet from the other machine, so for some reason it is being shared by that machine, and this machine prefers the lan over wifi.

How can I either stop the internet sharing on the server, or force this other machine, to only use the net from wifi?

I know it would be easier to use a router, but there is a performance decrease, among other things.

This machine is SUSE 12.1 Gnome 3 64 bit, the other is Mint 9 32 bit. Both have pretty similar connection managers.

You seem not only to have multiple connections, but also double posts.

Please do not double post.

I will CLOSE this one. All please post in the other one: http://forums.opensuse.org/english/get-technical-help-here/network-internet/471408-multiple-connections-net-only-one.html