Symmetric NAT Traversal using STUN

Document Type Expired Internet-Draft (individual)
Last updated 2003-06-06
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It is generally known that the binding acquisition for symmetric NATs with STUN (Simple Traversal of UDP through NATs) protocol will not yield a usable address for traversing symmetric NAT. The use of symmetric RTP allows you to accompolish symmetric NAT traversal only in situations where the other end is open to the Internet, or has a full-cone or a restricted-cone NAT. This document proposes an analytical method for symmetric NATs to obtain more detailed characteristics of the symmetric NAT using STUN, and describes how we can establish a peer-to-peer UDP connection even in situations where NATs (including symmetric NATs) are present at both ends.


Yutaka Takeda (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)