Hi guys quick question in regards to the differences in IAX and SIP trunks.
I have FreePBX here behind pfsense firewall. I am trying to connect a remote SIP trunk but has audio issues. After 2 days of mucking around trying to get this working through NAT with static ports etc I gave up.
Reason for this is I have two mobile phones with Zoiper loaded which I would like to connect to my Asterix server to make calls and dial local extensions.
I have found using IAX this has resolved my audio issues from the quick testing I have done so far.
IAX2 is much less problematic historically than NAT. It also only needs one port opened (4569/UDP) on your firewall should you need to open it up for remote access. Also there is a lot less scanning and hacking out their for IAX2 protocol than for SIP (which gets scanned and has constant hacking attempts if you open it up to the Internet). So if IAX2 works for you I would stick with that for Zoiper as your softphone.