can i setup outernet with dvb-s or dvb-s2 and jast a pc (windows or linux)?
In theory you could do that. But there are two limitations in practice that make an extra part or two needed.
Signal and Noise. There just is not enough signal from the satellite to have the stock DVB stick to hear it well. So you need a pre-amp at the antenna to boost the signal. This pre-amp is cheap to buy, but it needs power sent up the cable to make it work. Most stock DVB sticks do not have the ability to send this power out. But shop around, you can find ones like outernet sells that do have the power option.
Frequency stability. Most DVB sticks drift more than the sdr software can track. So a Temp Compensated Crystal Oscillator is used to hold this in check. Just as above most DVB sticks only have a basic Crystal Oscillator so they go off frequency to much. As above the one outernet sells has this feature as well.
You can try it with a Linux package (or VM under windows) but it is not a supported platform at this time.
There is no Outernet on DVB-S anymore!
It is now on L-band and it requires a DVB-T stick.