[asterisk-users] Using dproxy to solve "no DNS hangs everything"problem?

[Brian Capouch]

James Harper wrote:
> 
> 
> This is a problem that affects more than just asterisk, so I'm sure
> there are solutions out there!
> 
> One thing you might do is to put a trailing '.' on all fully qualified
> DNS names. Without the '.', the system will first try appending the
> default domain(s), which will cause extra lookups and delays. If all the
> names that you care about can be resolved locally without needing the
> internet then the trailing '.' should make it work much faster.
> 
> Of course, I'm assuming that you do have a local DNS of some sort, and
> the delays you are seeing are caused by your systems thinking they want
> to look up external names.
> 

Well after three hours of playing, and knowing it's rank awful to 
respond to your own posts, I would like to review what I've learned and 
maybe save someone else a few million headaches.

I installed dproxy, which is a caching nameserver, and thought at first 
my problems were all solved.  I could lookup names just fine on the 
machine, I saw the names show up in the dproxy cache file (including the 
names of the IAX and SIP servers I register with).  I made a test call 
through one of my ITSPs and it worked just fine.

Then the sky fell: a PSTN call came in, and as the server rang the 
phones in the house (one of which is a SIP phone) things locked up 
tight, just like there wasn't any DNS!!

I did a little boinking around on the CLI, and noticed that all my IAX 
registrations had gone just fine, BUT NOT ONE OF THE SIP REGISTRATIONS 
succeeded.

I'll cut to the quick, although I have to disclaim this as "the best 
guess I have:" it turns out that if the DNS server the Asterisk box is 
pointing to doesn't do SRV lookups, and "srvlookup=yes" in sip.conf, 
it's Goodbye Joe.

I set that option to "no" and restarted.  Now everything appears to be 
working just fine.

Whew.

B.

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