After my recent post about using SNGREP and HEP for TLS SIP capture with Freeswitch, not only did the Freeswitch team merge my patch that enabled better SIP capture with HEP, but Anthony Minessale (Freeswitch project creator) invited me to talk about my recent work in this area on their Cluecon Weekly video chat.
Encrypt all the things! This has been a popular sentiment in the open source community for the last few years. And with the rise of Lets Encrypt this has never been easier and cheaper to do.
One industry that hasn’t been so quick to adopt these new secure mentalities are wholesale VoIP providers. But this is changing and providers like Simwood, Voxbone, DIDLogic and Twilio now offer encrypted voice calls using SIP over TLS with SRTP media.
Zoiper 5 and Freeswitch 1.6 don't allow encrypted calls to work out of the box due to a bug in Freeswitch with some of the newer RTP/SDES encryption suites.
After much time spent with the Zoiper support team (who are awesome by the way!), they suggested changing the cipher preference order in Freeswitch to disable some of the new suites that Freeswitch does not support fully.