our PBX is having an issue with inbound calls to a specific provider that we connect to via registration. We have other providers we connect to by them allowing our IP and we have no issues.
At present we have a cron job running that does "sip reload" every minutes as this does fix the issue. But we don't always get a full minute of inbound calls, and we are loosing them. When looking at the CLI when its not working there is no activity. So we thought it could be a firewall issue.
We are using a Sonicwall NSA 220 and it is configured correctly port wise. We also decided to allow all traffic from the ip range of the provider "Voip Unlimited" so rule out ant porting issues but this has not helped.
Does anyone have an idea on what it could be? Also by running sip reload it fixes it, but we are not sure exactly what sip reload does?
Before responding please read my whole question, as its a pain when someone replies with nonsense.