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DNS address - which one ~ rules~

Discussion in 'General Wireless Discussion' started by frankhere, Mar 6, 2020.

  1. frankhere

    frankhere Occasional Visitor

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    Folks,
    If I set my router to a specific DNS address ( say , Google 8.8.8.8) and another device ( notebook or desktop computer) has a different DNS address set in their config, which one rules?

    Is there a hierarchy ?

    Any thoughts on this?

    thanks!!!
     
  2. hyelton

    hyelton Senior Member

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    What you set on the computer will rule out what the router is set too

    Sent from my SM-G981U1 using Tapatalk
     
    psychopomp1 likes this.
  3. ColinTaylor

    ColinTaylor Part of the Furniture

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    ... unless your router intercepts and changes the client's DNS query destination address (like DNSFilter does in Merlin's firmware).
     
  4. frankhere

    frankhere Occasional Visitor

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    ahhh! and that was what I was looking for. Then you do not have to monkey around with all the devices.
    you also can fine tune a home network (me thinks) in a more reasonable way to see if there are any performance improvements with the testing of different DNS services.

    Yet from an academic point of view it SEEMS to me the router should always trump any other device choice on DNS selection.... as it is the manager of the traffic out to internet. At least that is how I think about it.

    thanks again for answering folks. Appreciated.
     
  5. ColinTaylor

    ColinTaylor Part of the Furniture

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    Most home routers have their own built-in DNS server that does caching and forwarding to the upstream server(s) defined for the WAN interface. So clients should be configured to use that.

    This is usually the most efficient setup because many DNS queries can be answered from the router's local cache (< 1ms) rather than having to go out to the internet. Of course for those queries that can't be answered from the cache the speed and reliability of the upstream server is still important.
     
  6. RMerlin

    RMerlin Super Moderator

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    DNS queries are made by clients, therefore it's not the job of the router to hijack and redirect these - that would be a non-standard behaviour, which can break various things. For instance if you wanted to configure your children's computer to use a DNS server such as Cleanbrowsing, or you had a Windows domain controller.

    What a home router normally does is provide clients with the address of the DNS they can use, when these clients use DHCP to obtain network parameters. A client choosing to use hardcoded settings rather than obtaining them through DHCP should then be the ones to decide since DNS resolving is their job, not the router.

    All a router can do in a clean design is present itself as the LAN's network resolver, so it can act as a cache. Blindly overriding should be considered non-standard, and be purely optional.
     
    L&LD likes this.
  7. psychopomp1

    psychopomp1 Senior Member

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    This seems to be the case. My router has Cloudflare DNS (1.1.1.1 & 1.0.0.1) setup. However when i change the DNS to 8.8.8.8 on a local PC connected to the router, that PC is now using google DNS. So it appears the DNS address on the client overides the DNS on the router.
     
  8. frankhere

    frankhere Occasional Visitor

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    Dec 21, 2019
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    thanks...
    nice... clear and logical.