One way calls

Hello, I’m a newbie. I’ve being trying to set up a home pbx (following the instructions for the online book about asterisk). My sip provider is inphonex. I’m using Fedora 11. I have ports 5060, 10K-20K open. I can make domestics calls just fine. However, some of my international calls, I hear the people I call, but they don’t hear me.

I have google the issue with no luck. Can any one suggest a solution? Let me know if you need my sip.conf and extension.conf


I don’t know why, but I removed festival and that seems to have solved the problem? I’m using Asterisk 1.6. Has anyone experienced this before?