Brian Capouch
2006-Jul-18 16:22 UTC
[asterisk-users] Using dproxy to solve "no DNS hangs everything" problem?
The subject pretty much says it. Wondering if there's anyone out there who, as an alternative to hard-coding IP addresses in /etc/hosts, has implemented dproxy or somesuch to enable Asterisk to survive DNS outages. I had a royal mess on my hands this morning after my Internet connection went down for a while. No DNS = No Anything if there are FQDNs in the conf files. The server hangs, affecting the Zap stuff too, which is WAY bad for me. I need to bite this particular bullet. My POTS line was offhook all morning because my Internet was out, and the first call that came in caused everything to freeze up and the channels were all hung. Thanks. B. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
James Harper
2006-Jul-18 16:38 UTC
[asterisk-users] Using dproxy to solve "no DNS hangs everything"problem?
> > The subject pretty much says it. > > Wondering if there's anyone out there who, as an alternative to > hard-coding IP addresses in /etc/hosts, has implemented dproxy or > somesuch to enable Asterisk to survive DNS outages. > > I had a royal mess on my hands this morning after my Internetconnection> went down for a while. No DNS = No Anything if there are FQDNs in the > conf files. The server hangs, affecting the Zap stuff too, which isWAY> bad for me. > > I need to bite this particular bullet. My POTS line was offhook all > morning because my Internet was out, and the first call that came in > caused everything to freeze up and the channels were all hung. >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. James
Brent Torrenga
2006-Jul-19 06:36 UTC
[asterisk-users] Re: Using dproxy to solve "no DNS hangs everything" problem?
Yeah, I thought dnsmasq was the cure, too. We had an internet outage last week. It was odd, our ISP (AT&T) changed out static IP's (don't ask... No one knows why... At least I figured out what was going on...). Thus, our modem/router was whacked, as well as our firewall. So, I think every piece of hardware saw the link as being up, but of course routing was not operating. For clarity, dnsmasq is installed on our firewall, a PC that routes traffic to our modem/router. As far as I understand, the way dnsmasq works is that it proxys DNS requests to your ISP's DNS servers (or wherever). At some point, if dnsmasq determines that the upstream DNS servers are down/unreachable, then it will respond to DNS requests with a failure/immediately timeout, thus precluding Asterisk from hanging while it waits for a DNS query. Sounds like a good fix for our problem, right? Well, last week it did not behave well. Calls on Zap channels came in, they would sit for several seconds (maybe 20-30, oddly some callers sat through that silence just waiting!), then when no SIP phones could be found it would go to the IVR (all attendants are busy, leave a message, etc...). All connectivity with the SIP phones was gone, even trying to initiate a call from the phones (Cisco _79[46]0's) to the Asterisk server was out. All connectivity on the local LAN was good, even dnsmasq serving the local DNS names. Can anyone explain why Asterisk would not ring the SIP phones on our LAN? The phones all register with the Asterisk server, the Asterisk server does not need to look anything up to contact the IP's of the SIP phones on the local LAN. I just don't know which direction to turn here.>Thanks Brian for your work, I have had the same problem I installed >dnsmasq and I *think* the problem is gone now, I'm repeating I think, >I'll only know when the internet goes down again.Sincerely, Brent A. Torrenga Torrenga Engineering, Inc. 907 Ridge Road Munster, Indiana 46321-1771 tel:+1 219 836 8918 x325 fax:+1 219 836 1138 email:brent.torrenga@torrenga.com web:www.torrenga.com