Will you laugh if I say "an old PC and a Prism2 card in an ISA bridge"?

I run Linux on it, and the flexibility is incredible, but I will admit that since in addition to simple routing it's also a tunnel endpoint it may be less interesting to you. Some traffic uses real IP addresses via the tunnel while other traffic gets NAT'd directly onto the internet, based on port and IP rules.

The internal wired and wireless are bridged, so if I want to switch my laptop from wireless to wired or vice versa I can do it without changing addresses; No "agent", all of my connections just stay open.