I want to tell a very strange issue occoured some weeks ago using pbx Asterisk 1.8, an router/firewall Sonicwall TZ 100 and a famous Voip ISP.
The system has always worked fine until a couple of weeks ago (pls see in linkografia for config used in Sonicwall TZ100).
Without any warning one day calls began to be randomly “one way”: the caller can hear but the called cannot. Briefly here is what we have verified togheter with the Voip ISP customer care.