[asterisk-users] asterisk slows down when unplugging internet cable with VoIP lines

[Giorgio Incantalupo]

Hi Alex,
thank for your tips. It seems that using IP instead or URL inside 
sip.conf is working good. This means Asterisk is not using /etc/hosts at 
all.

Thank again!

Giorgio


Alex Robar wrote:
> Hi Giorgio,
>
> LOTS of people have had this issue, check the list archives for some 
> other responses.
>
> You are quite correct, Asterisk DNS is synchronous, so when your 
> internet connection goes down, it causes some problems for the rest of 
> the system. There are a couple of ways of handling this:
>
> 1) Don't use DNS. Use IP's in your Asterisk conf files instead of 
> hostnames. (Make sure there are no hostnames ANYWHERE in the conf files).
>
> 2) Use an internal DNS server/cache. Setup a DNS server that caches 
> queries somewhere on your network (or on the Asterisk box itself, if 
> you're unable to put it somewhere else on the network). Set the 
> Asterisk box to use your internal DNS server. This way, even if the 
> internet goes down, Zap calls and internal calls will still be routed, 
> as Asterisk will still be able perform DNS lookups.
>
> Both of these options have the downside that if your provider changes 
> their IP, nothing works and you'll have to either change all your conf 
> files (option 1) or clear your DNS cache and force a lookup again 
> (option 2). However, most providers won't change the IP on your, and I 
> would hope that if they did, they would notify their customers ahead 
> of time.
>
> Cheers,
> Alex Robar
>
> On 4/26/07, *Giorgio Incantalupo* <gincantalupo at fgasoftware.com 
> <mailto:gincantalupo at fgasoftware.com>> wrote:
>
>     Hi,
>     I have an Asterisk 1.2.9.1 <http://1.2.9.1> on a Debian Sarge
>     distro connected to a VoIP
>     provider via internet.
>     I noticed Asterisk gets slow and  behaves in strange manner if I
>     unplug
>     my internet cable from the PBX: for example I get incoming calls after
>     seconds or I get no audio during calls.
>     I thought it was something connected to DNS resolution so I put VoIP
>     provider addresses inside /etc/hosts but still have slow problems.
>     I made some tests adding registrations to providers inside sip.conf
>     keeping my PBX disconnected from internet: after a "sip reload"
>     the CLI
>     simply stay freezed waiting for something. Trying to "sip reload"
>     gives
>     a message Asterisk is still waiting to perform the last reload. A
>     real mess!
>     I read on internet, inside dns.h file reference, Asterisk is using
>     synchronous dns functions...infact a note explains that:
>     "Asterisk DNS is synchronus at this time. This means that if your DNS
>     does not work properly, Asterisk might not start properly or a channel
>     may lock"
>     How can it be? If this should be true this would be a big problem with
>     VoIP lines since losing internet connections is not so uncommon
>     (if so,
>     why nobody else got this trouble?)
>     Is it possible to bypass this behaviour or should I avoid VoIP
>     lines??
>
>     TIA
>
>     Giorgio Incantalupo
>
>
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>
> -- 
> Alex Robar
> alex.robar at gmail.com <mailto:alex.robar at gmail.com>
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