"S.J.Chun" <chunsj at embian.com> asks

> I'm trying to create P2P application which can work around NAT.
> It seems that Aardworks already done reliable UDP communication,
> and I want to know if there's some doc on it.

The Session Initiation Protocol people have wrestled with NATs (as have most
people), and they wrote a very handy document on the subject:

http://www.ietf.org/internet-drafts/draft-ietf-sipping-nat-scenarios-07.txt

While it's a SIP document, the information is relevant to most (all?) P2P
applications needing to traverse NATs.

Some other documents (from the above URL's References section) are

* RFC 3424 ("IAB Considerations for UNilateral Self-Address Fixing (UNSAF)
Across Network Address Translation")
* draft-ietf-behave-rfc3489bis-07 ("Session Traversal Utilities for (NAT)
(STUN)")
* draft-ietf-behave-nat-udp-08 ("NAT Behavioral Requirements for Unicast
UDP")

frank