Peter Ford wrote: > If one really believes in end to end architectures, then one probably > would want generalized protocols for supporting hosts telling the > network what to do wrt opening holes at NATs/Firewalls for inbound > traffic. Actually, if one believes in the E2E arch (more specifically, the STD documents), we should admit that: - NATs are _designed_ to make everything behind them look like a single host - they work fine exactly where that's sufficient - they break very badly for EVERY new protocol that coordinates ports or IP addresses in-band, and in any other case where everything behind them does NOT want to work like a single host A generalized protocol for opening holes would fundamentally alter the Internet architecture (as specified in the STD docs) to _require_ path setup, which defeats dynamic routing, and, more specifically, the fundamentally connection-free property of datagram service. Joe