mariuszp wrote:
If I connect the machine through ethernet to a DSL model, and then into the wall, will the machine have direct access to the internet (without NAT)?
It depends on your modem. If the modem's a gateway, it will perform network address translation for the machine behind it. If it's a switch or a bridge (the more "dumb" kind of device), it will not; the DSL frames will be translated directly to Ethernet frames and sent to your machine. Theoretically there's no need for a modem to perform network address translation, but if the manufacturers decided to be "clever" they might well have made it a NAT (more like a single-port router really).
You'll also want to be careful, as your ISP contract may well have a term that says that you have to use their supplied hardware. Whether or not they'll be able to detect that you're not using their hardware depends on how you configure the replacement hardware - if you configure it to mimic the supplied hardware almost exactly they'll probably never notice; if you start doing weird things like tunnelling IPv6 connections and not using their own IPv6 configuration, they might notice pretty quickly. I know it seems stupid to mimic the supplied hardware when you're trying to improve on it, but you might just want to bear that in mind. (You could maybe try to mimic their hardware *and* do your own thing at the same time...)