[asterisk-users] No retry after DNS failure

[Remco Barendse]

> 
> If memory serves correctly, most of the above has been raised as issues in the
> past and the suggested work around has been to run a dns caching server on the
> asterisk box.
> 
> FWIW, I always use IP addresses instead of dns names. But, I don't have to
> deal with dynamic ip changes of any device either.
> 

I have also been bitten by this issue a number of times. When your 
internet connection is down a caching nameserver will not do you any good.

This is an extremely irritating 'feature' of asterisk. I have the same 
issue with my iax providers.

If outgoing calls are failing via voip I route my calls out through pstn. 
It is very frustrating to see * routing all those expensive calls out via 
pstn because it is not retrying to resolve the hostnames.

Furthermore I have seen providers doing some sort of load balancing by 
returning a different ip host to send the call to on new dns lookups. This 
will not work if * doesn't refresh the ip lookups.

I am aware that it could mean serious delays for a call to be completed if 
the dns lookup was done for every call but surely it should be possible 
for * to keep re-trying to resolve an ip address for previous failed 
entries let's say every minute or so? The added load is negligable.