What port do i plug in the xbox 360 ethernet cable on my router?

Question

I have 3 available lan ports on my neatgear router

Answer 1

ANY port besides WAN! DO NOT plug into WAN!

Plug it into 1, 2, or 3. Obviously one of the ports should have your DSL plugged in (I'm assuming that's why you have only 3 ports available, since your DSL is plugged in).

So yes, both your DSL and your 360 should be in 1, 2, 3, or 4.
NOT THE WAN!