Marc,
I saw your post in your blog and I am going to use it tonight. I do not use 2 ethernet ports although this is probably better. I only have a DD-WRT router connected to a Speedtouch 585v7 (as an ADSL modem in bridge mode) and my AMPRnet Gateway in a LinuxMint Box with one ethernet port and 4 radio ports in it's 4 x RS232 adaptors.
73 de Demetre SV1UY