Alternative DNS IP Address not being used(?) 1

[BobHLiton]

We have a setup where a NS700 is configured for two DNS servers but when then Preferred is offline it seems to not even try the Alternative DNS server.

The DNS servers are Windows domain controllers and they have to do Windows updates, unfortunately. And when this happens and the Preferred DNS server is unavailable for several minutes the phone system will not allow us to place any calls as service is over Internet.

I could understand this if there was only one DNS server but there is a secondary DC/DNS server for exactly this situation. The NS700 seemingly will not try the Alternative DNS server.

The Alternate DC/DNS server continues to service Windows clients and RADIUS clients while the Preferred is offline so it does not appear to be a problem with the Alternate DNS server.

Also unfortunate is whenever this happens the phone system never recovers in a timely manner and so we have to manually reset the NS700 after the Preferred DC/DNS server is again operational.

To confirm the configuration is located under Network Service > IP Address/Ports > Basic Settings > DNS Setting > Use the following DNS server address > Primary and Alternative.

It would be nice to have a DNS timeout settings so it will use the DNS cache for at least 15 minutes. The recent MS Updates can take a long time especially on older systems.

Thanks for reading. Any suggestions appreciated!

-Bob

 

[keypulse]

Can you not use your SIP provider's IP address instead of the FQDN?

 

[BobHLiton]

Hmm. Good point! It's on *.outboundproxy.com, part of Skyswitch

 

[keypulse]

Sorry, I'm only familiar with providers in the UK but I almost always use the IP. Might be worth chatting to your provider or reseller and asking the question.

 

[Ired]

Probably you should try to describe this problem to your dealer. Your dealer must confirm the problem. After that he can report it to Panasonic.

As an aternate solution: try to use DHCP-client feature at your PBX (not a static IP) - in that case you'll be able to get DNS-server address automatically from DHCP-server. Perhaps it will help.

 

[BobHLiton]

Well, I've egg on my face after discovering the second DNS server had somehow lost its default gateway for IPv4. Not sure if this was after Windows updates or how this happened. It's Server 2006 on HyperV. I'm now set to improve testing/monitoring our DNS services (open to any good ideas, we run Zabbix).