Wow! Dreamcast as an affordable router! (Score 4)

According to this portscan, the dreamcast supports BGP! For those of you who aren't familar with BGP, it's a policy-based routing protocol used (for instance) at the NAPs.

So does this mean that Sega is going to start selling routing cards for the dreamcast? It's good to see that someone's finally working on an internet device that isn't just a client, but an affordable router! It's high-time I got rid of that crappy Cisco we have over here and replaced it with a fine piece of networking machinery, like a Sega. I'm so happy to see a router that's not just cheap - but you can also play games on!!!

Seriously, though, it does indeed appear that your ISP is doing something silly redirecting ports. This is particularly probably since nobody else can recreate this test. Either that or Sega chose a really bad port number to bind on.