Outgoing VOIP call sometimes stops DNS working?

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sidefx

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#120815 14-Jun-2013 15:38

This is a bit of an odd one, but I've now observed it at least 3 times on my home network. Basically one of us will make an outgoing call and DNS lookups stop working. It's not every time, but I've now noticed it enough times that I'm pretty sure that's what's happening.

Connectivity seems fine it's DNS lookups that seem to stop working and time out until the call ends (for example it just happened and I had a citrix session that remained completely responsive throughout, but all dns lookups failed until the call ended)

Anybody have any suggestions on what might cause this? I'm running a Fritzbox as modem and ATA so wondering if there's a bug or something with their built in QoS for VOIP?

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sbiddle

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#836916 14-Jun-2013 16:32

What are you using for DNS lookups - external DNS or your router?

sidefx

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#836931 14-Jun-2013 16:57

Ah, that could be related. I'm using my Amahi home server as caching DNS server, which now that I look into it defaults to openDNS.

https://wiki.amahi.org/index.php/Changing_your_DNS_provider

Is it best to set it directly to my isp (snap) dns severs or just my modem/router?

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kamrind

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#836947 14-Jun-2013 17:34

Try setting the computers dns to use opendns as a test.

Also the next time it happens use command prompt and do a ping test to google.co.nz/.com

Remember that sometimes you may not have enough bandwidth to support both VOIP and internet data, and also if your modem supports it use WMM or WMI to help.

That was an issue for me aswell when i was on the DSL network, now that im fibre, its fine

kamrind

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#836948 14-Jun-2013 17:37

sidefx: Ah, that could be related. I'm using my Amahi home server as caching DNS server, which now that I look into it defaults to openDNS.

https://wiki.amahi.org/index.php/Changing_your_DNS_provider

Is it best to set it directly to my isp (snap) dns severs or just my modem/router?

If you change your DNS to say... OpenDNS and your ISP's (SNAP) DNS is down, then you'll be one of the only SNAP customers that can still get on the net. unless of course other people use other DNS providers aswell, then same applies to them

if its more than a DNS issue, depending on what it is for example if its a hardware issue at your exchange, you may not be able to access the internet even with the use of another DNS provider

Also there are two options to change your DNS, you can set it at each computer individually, or u can set it at the router/modem, but if its set at the modem, any computers that connect to the modem are forced to use the DNS set, unless that is u set it up at the computer