[asterisk-users] No retry after DNS failure

[John Marvin]

Today I had a brief power outage which caused the Asterisk server and 
DSL modem to reboot. The Asterisk server came up before the internet 
connection was working, so it failed when try to look up some of the 
hosts for my outbound voip providers in sip.conf.

Asterisk never recovered from that, i.e. it never retried so those 
providers were unavailable. The only provider that was still available 
was one that I had entered the IP address for, rather than the host name.

Have any of you run into this issue, and if so, how have you solved it? 
It seems that since Asterisk periodically tries to reregister it should 
also retry the DNS lookup at the same time, rather than never trying 
again if the lookup fails. This would indicate that Asterisk would also 
fail if the voip provider changed the IP address of its server because 
Asterisk would never see the new IP address.

Here are some workarounds I thought of, but none of them are 
particularly good:

1) Get a UPS so my machines won't reboot when the power fails. This 
actually might not solve anything, because I'm connected to a remote 
DSLAM in my neighborhood that I believe does not have backup power, so 
it won't work when the power is out. But perhaps Asterisk is more robust 
after it has booted (I'll have to test this).

2) Change all host names in sip.conf to IP addresses. This is kind of 
ugly and also will break when a voip provider changes their IP address. 
There is a reason for DNS!

3) Have a cron job send asterisk periodic "sip reload" commands.

4) Delay the start of asterisk until the internet connection has come 
up. This could cause me to be without any phones if there is any delay 
or failure in bringing up the network (I also have zap channels and PSTN 
lines).

5) A hybrid of ideas 3 and 4 above: Have a startup script that waits for 
the internet connection to come up, and then sends a "sip reload" 
command to Asterisk.

Any other ideas?

John