http://retinal.dehy.de/docs/ 2026-05-09T23:09:23+02:00 http://retinal.dehy.de/docs/ http://retinal.dehy.de/docs/lib/tpl/minimal/images/favicon.ico text/html 2021-10-23T15:04:04+02:00 http://retinal.dehy.de/docs/doku.php?id=technotes:usingfreeswitch:freeswitchnat&rev=1634994244&do=diff Anyone who's played with SIP knows that the nutters who designed that protocol (in the late 1990s; RFC 2543 was published in 1999) totally failed to learn from the problems with FTP from the early 1970s and Network Address Translation, by burying IP addresses inside the layer 7 protocol and hence causing all sort of problems when either your telephone (most commonly) or your PBX (less often) or even both (a terrible combination to get working) is behind a NAT router (such as nearly everyone has …