I have a simple question. When and how often does Asterisk resolve the IP address of the provider’s domain name? I had always made the assumption that Asterisk only does a single domain resolution once at start-up then caches the address. I am working with a client who is consistently receiving messages indicating all circuits are busy and other strange behavior. After some digging around I realized their ‘previous’ admin never configured DNS forwards on their Windows DNS server which means every DNS request was timing out before hitting their DSL router which then did a recursive DNS request to the provider’s DNS server. This lag was never noticeable until a few weeks ago when I suspect some additional load has been placed on the provider’s DNS server introducing additional latency.
This also made me wonder if I shouldn’t be advising clients to add the trixbox server address to the DNS forward and reverse look up zones when possible? Does Switchvox/Trixbox/Asterisk try to resolve its own hostname via DNS?
I should note the two may not be related. I am just curious how and why Asterisk works the way it does. Thank you for sharing your knowledge!