Summary:	ASTERISK-06858: unresponsive DNS servers cause asterisk to pause for extended periods during startup
Reporter:	evilbunny (evilbunny)	Labels:
Date Opened:	2006-04-27 10:34:26	Date Closed:	2011-06-07 14:07:46
Priority:	Minor	Regression?	No
Status:	Closed/Complete	Components:	Core/General
Versions:		Frequency of Occurrence
Related Issues:
Environment:		Attachments:
Description:	due to network outage one of the register/peers in my sip.conf name servers weren't able to be reached, so asterisk locked half started up waiting for a DNS reply.... which is bad m'kay... I'd suggest the quick fix is handle dns lookups etc after asterisk has fully loaded, or run them in parallel...
Comments:	By: Andrey S Pankov (casper) 2006-04-27 11:11:07 Are you sure it is paused in main asterisk, not in a channel driver? By: Andrey S Pankov (casper) 2006-04-27 11:17:45 As a workaround you may use /etc/hosts if it's configured to be used first... By: evilbunny (evilbunny) 2006-04-27 17:51:07 I'm not sure where it paused, but it was only half done loading asterisk, while changing to IPs, or setting the host is a work around, are you planning to tell every asterisk user this or perhaps the problem should be fixed instead :) By: Andrey S Pankov (casper) 2006-04-27 18:29:29 There even were places in the code with "can block for a long period of time" because of gethostbyname. That's normal I think... Can you imagine the configuration of static peers without IP address. How can we know you have troubles with your DNS resolver until a name fails to resolve? Any ideas? By: evilbunny (evilbunny) 2006-04-27 18:32:29 All the error messages afterwards about unable to lookup sort of gives the fact away that something is wrong... Alternatively perhaps the easier fix is a hard timeout of 5 seconds on dns lookups... While it will still lock on startup, it should be minimal compared to the minute or 2 per hostname now... By: Serge Vecher (serge-v) 2006-05-08 12:58:21 evilbunny: still need to know what channel drivers are in use here ... By: Andrey S Pankov (casper) 2006-05-08 13:14:56 Let's close this for now. It is a support issue. One need to have a reliably working DNS server. This does not require any changes to the Asterisk code. By: Serge Vecher (serge-v) 2006-05-08 13:22:49 well, we need not wait up to 2 mins per hostname at startup either. IMHO, evilbunny's suggestion of making dns timeout an option in the channel driver or elsewhere has merit. By: Andrey S Pankov (casper) 2006-05-08 14:10:06 vechers: and I stress on it again, this is a support issue. 'man 5 resolv.conf' or http://www.google.com/search?q=resolv.conf Now I wondering who will send me $50 for that... :( By: evilbunny (evilbunny) 2006-05-08 20:42:40 I think you misunderstand, it's not my DNS servers that were unreachable, it was the VSPs due to them having a network outage... By: Olle Johansson (oej) 2006-05-09 10:13:17 This is a known problem on the "to-fix" list together with evilbunny's other enum problem. It's not a quick fix at all and, as I said, well known. By: Joshua C. Colp (jcolp) 2006-05-19 09:24:13 I'm moving this to SVN trunk since in order to fix it, we'd have to do some MAJOR changes that I doubt would make it back to 1.2. Now - as others have said, this IS a very known about issue... and one of the ways to solve it outside of Asterisk that does work is to use something like dnsmasq which is a caching DNS proxy. By: Russell Bryant (russell) 2006-05-19 09:31:55 The other question at hand is that is this really something that we should try to handle inside of Asterisk?  Should Asterisk really be expected to work normally in a broken network situation?  My vote is no ... By: Joshua C. Colp (jcolp) 2006-05-19 11:49:07 Let's move future discussion of this to the asterisk-dev mailing list. See you there, everyone!