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Upstream DNS Server Query Order
Hi, In NxFilter we have all 3 Upstream DNS fields filled in, however, we want #1 to be exclusively used unless it goes down, and only then it should go to #2 or #3 in case #2 is down as well. How can I accomplish that? Currently it seems like it goes to the fastest instead. Thanks.
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It already works that way if you use the latest version. However, you better use the upstream servers from one company in same region. There might be difference in their DNS answers if you use upstream servers from different companies. It will cause you troubles with CDN sites especially. -
First of all, I had to go back to the old GUI, because it has "Use Load Balance", which seems to be missing in the new GUI and was still enabled. However, that still didn't do the trick, the only thing that consistently works is to leave Upstream DNS Server #2 empty, thus only fill in #1 and #3 at this point it will only use #1 and automatically switch to #3 when #1 is down. As soon as #1 is back up, it will automatically start using that again.Comment
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Those functions are from our library not from us. So, we don't know how it works exactly. We will test it.
We know that Load Balancing missing in GUI. It's because there were people using DNS servers from different companies and different regions. And they had troubles with DNS resolving. It appeared like some websites not working for some users only. These people already reported it as a problem of our cache. Especially Persistent Cache. But it turned out to be the problem of mixing DNS serves from multiple companies.
So, we don't like to do something with these multiple upstream DNS servers. And we retreat to using only fail-safe by using multiple upstream servers. However, some people might like to use that Load Balancing even though it's primitive round robin way. That's why we left it on old GUI but removed from new GUI.
We will test this one thoroughly next week. It may take some time as we need to set up several DNS servers.Comment
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Luckily for us it works by just leaving the Upstream #2 empty and disabling Load Balancing, so we are all good. 👍Comment
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I added #1, #2, #3 upstream DNS servers. When one of them goes down, the next one takes the job. However, in my case, it starts with #2. I don't know how it decides the order. Could be related to IP address. We can make it starting with #1 but that cost too much. We need to build our own module for that. What we gain is only that it starts with #1. And in most cases, 2 DNS servers would be enough and if they are from the same company in the same region, the order wouldn't be important I guess.
If you are worry about losing connection to your upstream DNS server, it might be better to use a local recursive server on NxFilter. You can install MaraDNS or Unboud on your NxFilter server and change their port to UDP/5353 and set your Upstream DNS Server #1 to '127.0.0.1:5353'. Then your NxFilter server has its own recursive server.Comment
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Don't worry about it. I already solved our issue by leaving #2 blank. We only need 2 DNS upstream servers, so having just #1 + #3 works for us. But it's good to know that when all 3 are filled in, that it starts with #2. I will look into setting up a local recursive server, that is actually a pretty good idea 👍Comment
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