Asterisk 1.8 and ZRTP


I wonder whether the passthrough of ZRTP packets has ben included into Asterisk 1.8 or if I’ve got to patch the sources somehow!


PrivateGSM Mobile ZRTP end-to-end client for iPhone, Blackberry and Nokia S60 phones had fixed the problem of ZRTP getting blocked by Asterisk on client-side.

If you read on PrivateWave ZRTP’s page … /zrtp.html:
“ZRTP protocol, by itself, does not work across a certain PBX (for example, Asterisk block it). PrivateWave technology extended the protocol with some light modifications, called ZRTP Masquerading. It allows the protocol to function with a non-ZRTP supported PBX as well.”

So with client side ZRTP Masquerading feature of PrivateGSM, the ZRTP packets are masqued like standard RTP packets and goes across Asterisk.

The client can be downloaded from and include mandatory support for SIP/TLS with TLS strict certificate verification.

Fabio Pietrosanti