Is a primary DNS faster then the secondary DNS of one provider?

Specifically google and Most people set as primary therefore its load is higher than the secondaries. Do I have a small speed gain when setting as my primary DNS?


You have to bear in mind what quicker means in terms of DNS speed. Even if there were a case for one name server being quicker than another you are looking at a few ms at the top of the session. All queries to that same address are going to come out of your computer's cache for probably the next hour or so.

I've just pointed dig at both servers and done a few arbitrary searches, and both are coming back (with knowingly cached answers) in ~10ms with non cached replies coming back in ~120ms

Also consider that this isn't a couple of servers that they've got stuck in the back of a server room, it is a massive distributed network in its own right. Google have the capacity to make sure that both servers are running with good request times. In fact you would probably find that all that has happened as a result of being more popular than is that the former has a lot more servers running it and I would be reasonably certain that response time is a metric that they use to scale with.

A final consideration, since many more people (probably) use it is likely to have a lot more answers cached. So actually you might find that in some cases the secondary could be in the region of 100ms slower.


No, not based on my experience and testing. I assume google has a pretty good load balance infrastructure in front of the actual DNS servers and you are just hitting those - at the end both IPs might be answered by the same server.

You can verify yourself using tools such as DNS tools

but make sure you test on at least 5000 domains


The DNS request first goes to the Primary DNS and will check the Secondary DNS if the Primary does not provide the address it was looking for.

Since we're talking about Google here for a client-side implementation of their DNS and even as a resolver for a server, we can be certain the Google has properly distributed their DNS and has all of these optimally optimized!

Things to consider in choosing a DNS considering performance.

  1. How many Servers are they running?
  2. Are they properly distributed and using Anycast?
  3. Are the Servers close to your location?

Google has Servers all around the world. Here's a list of Google DNS Servers. This makes the DNS server run faster compare to other DNS provides with smaller networks. tpe bru grq mrn mrn tpe atl tul mrn tul lpp bru cbf bru lpp chs cbf chs chs dls cbf mrn mrn atl atl chs bru cbf cbf chs chs dls dls sin tul cbf scl bru tpe tul dub lpp tul
2001:4860:400b::/48 dls
2404:6800:4003::/48 sin
2404:6800:4008::/48 tpe
2607:f8b0:4001::/48 cbf
2607:f8b0:4002::/48 atl
2607:f8b0:4003::/48 tul
2607:f8b0:400c::/48 chs
2607:f8b0:400d::/48 mrn
2607:f8b0:400e::/48 dls
2800:3f0:4003::/48 scl
2a00:1450:400b::/48 dub
2a00:1450:400c::/48 bru
2a00:1450:4010::/48 lpp
2a00:1450:4013::/48 grq

Google Public DNS uses anycast routing to direct all packets to the closest DNS server. About anaycast here

Since Google's servers are globally distributed, there is a high chance of one being close to you.

  • That isn't actually a list of Google's DNS servers, it is a list of the subnets that they operate from. There are quite a few there that are duplicated at the same location, which could mean a single server or multiple servers at one or many locations
    – Michael B
    Apr 16 '16 at 12:28

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