I have set up SIP trunks with provider. I am getting one way audio. When I call out via SIP Trunk the person outside the MITEL can hear me however I can't hear them on mitel also I'm not getting ringback while call is ringing. I am not using MBG. My IT Dept is NAT'ing via a Palo Alto firewall. It seems like it is a maybe a RTP issue. Just curious could I see one way audio in a SIP Trace, if so what would it look like. Any help appreciated