This Recommendation extends ITU-T Rec. H.323 by defining the NAT/FW traversal mechanism for media. Together with an appropriate mechanism for signalling traversal, such as H.460.18, it may be used as a solution for the NAT/FW traversal problem by H.323.

This revised version introduces a number of clarifications to the previous version by incorporating the technical and editorial corrections from the H.323-series Implementers Guide (03/2011).