I’m quite new to Asterisk and using Asterisk 13 on FreeBSD current. Asterisk is behind a NAT router, the physical setup is very much a trivial one. The Asterisk PBX is supposed to act as the telephone gateway for several VoIP/SIP phones.
I’m using throughout pjsip as configuration, I have no experience with chan_sip since I
started recently using Asterisk for several SoHo and lab’s projects. So be alarmed, there may come some noobish questions.
When planning and setting up the Asterisk, I had to deal with NAT. The Asterisk config object of type=transport knows about essential entries:
external_media_address= dyndns FQDN
external_signaling_address= dyndns FQDN
direct_media= no rtp_symmetric= yes force_rport= yes
dyndns FQDN is the FQDN of my broadband access point provided by some dynamical DNS
This setup is not working properly with when external_media_address= and external_signaling_address= are set that way, but commenting out both makes all of the ITSP which provides me with service happy.
I think, at this point I have no idea of the concept or, there is simply a missing link, even a (dangerously) misconfigured router – on which the Asterisk runs. When external_xxxx_xxxx are not set, I suppose they’re set to 0.0.0.0/0.0.0.0, aren’t they, implying that they listen on all configured IPs?
If so, is there a way to show the setting of external_media_address= and external_signaling_address= on the CLI?
When using PJSIP with the setting excluding attributes external_xxx_xxx, does pjsip do some magic to traverse the NAT in a proper way? At this very moment, I do not understand how things would work avoiding setting external_media_address= and external_signaling_address=. The Asterisk 13 I’m running is supposed to be bound to IP
192.168.254.1, which is routed to the gateway.
My problem is, I don not understand why the communication is working fluently with both external_xxx_xxx atrributes commeneted out which I suppose to be crucial – following the Asterisk 13 documentation!
Maybe someone can sched some light onto this. I think, my view on the matter is completely confused.
Thanks in advance,