Signalling the Presence of NAT

Document Type Expired Internet-Draft (individual)
Authors Ray Bellis  , Geoff Huston 
Last updated 2012-04-25 (latest revision 2011-10-23)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


End-to-end applications have difficulty distinguishing between packets that have been passed through a Network Address Translator (NAT) and packets that have been passed along a clear end-to-end path. We propose mechanisms for IPv4 and IPv6 whereby NAT devices explicitly signal their operation as a means of allowing applications to distinguish the presence of otherwise undetected NATs in the end- to-end path.


Ray Bellis (
Geoff Huston (

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