Can/should the Linode DNS resolvers be used as DNS forwarders?
I run my own DNS servers in two of my Linodes.
On the definition of a Linode's network settings, like on a
https://cloud.linode.com/linodes/nnnnnn/networking
there is both 'DNS Resolvers (IPv4): nnn.nnn.nnn.nnn' and 'DNS Resolvers (IPv6): nnnn:nnnn::' specified.
I may be wrong, but I though it would be right to point at those IP addresses as 'forwarders' in my own Linode's local DNS configuration.
The idea being to ask Linode's DNS servers before bothering the root servers. Linode's DNS servers may have a much larger cache than my own DNS server, so I should quite often get the answers from the Linode DNS servers, and only if they don't know, should my DNS server go poke the root servers.
Is this thinking conceptually correct? Or am I trying to do something I shouldn't?
Reasons for asking:
1) The Linode 'DNS Resolvers' change now and then. Not often, but over the years, it's happened more than once for my own Linode(s). Which tend to make my own DNS server very slow, timing out the forwarders before deciding to go up to the root servers. It takes me 'a while' before I understand what's going on.
1.1) Is there a mechanism I can use to dynamically and periodically pull in the list of Linode's DNS Resolvers so that I can (script) compare the current list of 'DNS Resolvers' to my own list of 'forwarders'?
2) Sometimes I find the Linode 'DNS Resolvers' being 'flaky', sometimes up, sometimes down. Never all of them at the same time, but one or a few of them in a given moment. If my DNS server is 'lucky' it will make a request to a 'DNS Resolver' which is up. Otherwise, things go slow.
So, to be brief, should I or should I not point to those 'DNS Resolvers' as 'forwarders' from my own DNS server configuration?
Regards (the very best)
1 Reply
jdutton
Linode Staff
Hey @schaffter - while I'm not a DNS wizard by any means, I did a little digging around on your questions and found a couple things you might find useful.
DNS forwarding to Linode's resolvers is definitely something you can do. Your train of thought is right on track - ultimately, Linode's DNS resolvers will have a much larger cache to pull from, and it stands to reason that you would want queries to be directed there prior to hitting your own DNS servers, especially if you want to speed up queries. If you haven't done it already, I'd try out forwarding to see what the results are like, and if it's not getting the job done, revert back.
Something I found in this other Community thread was a user that suggested managing your DNS using Cloudflare's DNS service to achieve instant propagation. Since you're running your own DNS servers, I'm not sure if this would interest you, but I thought it was worth mentioning considering speed is a factor.
You also mentioned wanting to periodically pull from Linode's DNS resolver cache. Based on this Stack Exchange post, it sounds like this may be possible using a couple different types of DNS software on a DNS server setup for caching purposes. Along with the previous link, here's another guide on how to set something like that up via Geekflare.
Hopefully this gives you a couple things to work with. Let us know how it works out if you decide to set it up!