Internet Dies. Then PBX Croaks... Revisited

Alex728

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There's been a number of threads on here about people losing both internal and external call functionality when the Internet link goes down, and various workaround suggested (such as implementing caching DNS, using a SPA3102 spare trunk etc)

I've certainly tried implementing BIND but it didn't seem to do much and the Linksys ATA's/IP phones also tend to go a bit pear shaped (dropping audio after exactly 20 seconds) if there is no external net connection, although this now only seems to happen after a few minutes (so if the net is lost for <5 minutes things seem to stay working)

whilst looking for something else in /var/log/messages I found this from the last time our office net connection went a bit flakey.

The in built DNS server in the office router (a BT Business Hub returns the domain homeportal.gateway.2wire.net if it cannot get an external connection - on a browser this shows a BT logo and a message about the lack of connection)

but what this appears to show is that despite all the ATA's and IP phones in my office being set up with dotted IP addresses, Asterisk has invented a "hostname" which is the extension, then "-" then a 8 digit hex number (I replaced by nnnnnnnn in case this was a security risk to post it here) and then .local - and for some inexplicable reason trys to get DNS to resolve it :banghead:

what seems more confusing is the hex number after the extension changes with each different attempt to resolve the "domain"

I've no idea what happens during "normal" operation but I've posted this here in case it helps anyone work out what is going on with this ongoing issue...


Oct 8 10:10:05 pbx01b asterisk: gethostby*.getanswer: asked for "talk.orbtalk.co.uk", got "homeportal.gateway.2wire.net"
Oct 8 10:10:05 pbx01b asterisk: gethostby*.getanswer: asked for "205-nnnnnnnn.local", got "homeportal.gateway.2wire.net"
Oct 8 10:10:05 pbx01b asterisk: gethostby*.getanswer: asked for "202-nnnnnnnn.local", got "homeportal.gateway.2wire.net"
Oct 8 10:10:05 pbx01b asterisk: gethostby*.getanswer: asked for "200-nnnnnnnn.local", got "homeportal.gateway.2wire.net"
 
from: http://pbxinaflash.com/community/th...ernal-calls-allowed-is-this-normal.245/?t=245

For anyone else that might experience this same issue; that is, when you loose your internet connection your SIP extensions (local) remain registered to the PBXiaF server, but calls cannot be completed at all, it will get solve if you add to the sip_custom.conf the line:

srvlookup=yes

Apparently this was reported back from Asterisk version 1.2, but apparently it as been carried all the way to version 1.4.15 which is the one that PBXiaF is using. For further details, please check the following links:

http://www.voip-info.org/wiki/view/A...+SIP+srvlookup
http://bugs.digium.com/view.php?id=9057

If anyone else has a better explanation to this issue, please let me know as I am still a little puzzle by it.
Regards,
 
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