>there's no way it can be set higher than 255, and if the routers around you work properly, they will decrement TTL by (atleast) one for every packet coming trough. (exception: "transparent"-mode where routers pretend not to be there)
Hm. So all you need is a tunnel (gre, esp, whatever) to the router and you can send it TTL=255 messages from afar :-/