[e2e] using p2p overlays to overcome recursive NATs/realms

[Joe Touch]

Jon Crowcroft wrote:

> so the problem with most the proposed solutions to workign around nats
> is that they really assume there are only 2 realms - 
> the great unwashed internet, and the poor deprived natted user. 
> 
> the real situation is that packets might traverse multiple natted realms (c.f. realm
> specific ip) - in this scenario, discovering the mapping involves discovering a path of
> several mappings-
> 
> soluton might be to start a p2p service, which propgates mappings - take the ideas from
> stun, turn, rsip etc, and use them repeatedly...where multicast is available use it


Why replace one broken system (NATs) with another (P2Ps)?

The former breaks access to servers (behind NATs) - servers like 
automated configuration management (as deployed by Compaq, e.g.), MS 
Netmeting and other conferencing and telephony apps, gaming, etc.

The latter replicates Internet routing outside the network layer, 
potentially creating inefficient redundant traversals over congested links.

BTW, I've been hit by NATs twice in the past week -

1) at Stanford Univ at a workshop, where wireless service behind a NAT 
defeated (unclear as yet as to how) PPTP tunneling. The connection would 
get about halfway there, and die. The site administrators kept asserting 
their NAT box wasn't the issue; wired connections at the same site 
worked fine. One wonders how much money is being wasted debugging errors 
created by NATs.

2) SMC and Linksys sell what they both call "wireless Internet DSL 
routers". Sadly, they do just about everything _except_ route. They are 
NAT boxes, and their NAT function cannot be disabled.

The interesting question is why. Bridging is a much simpler function, 
and there are quite a few advanced features that require substantial 
network expertise.

Anywho, can't we all just speak IP? :-)

Joe