this post was submitted on 12 Jul 2024
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me_irl

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submitted 4 months ago* (last edited 2 months ago) by [email protected] to c/me_irl
 

It was definetly DNS

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[–] [email protected] 19 points 4 months ago (10 children)

It's called a secondary DNS server. Like, literally the reason it exists. I guess it's still on the line towards knowing what TF you're doing. Every DHCP server offers at least 2 dns server options.

[–] [email protected] 3 points 4 months ago (2 children)

Setting a second DNS in your router will bypass the pihole though, making it useless unless both servers point to a different pihole server

[–] suodrazah 1 points 4 months ago (1 children)

Kubernetes or Swarm, or a dozen other solutions to this.

[–] [email protected] 1 points 4 months ago

Care to elaborate? Last time I tried to set the secondary DNS as backup while keeping the pihole filtrering there was no real way to do it without having two piholes. Even the pihole developers said as much

[–] [email protected] 0 points 4 months ago* (last edited 4 months ago) (1 children)

A secondary DNS server set in your DHCP options will do no such thing.

The secondary DNS server is only used if lookups to the primary fail, say like when your pihole crashes or something.

The only way it will work the way you think it's going to, is if you set your DNS resolver to use round robin on a list of DNS servers.

Its literally just a backup DNS server address, and is only used should the primary fail, and returning an nxdomain is not a failure.

Please note, I use secondary to refer to the 2nd IP in your DHCP/DNS options, not to a secondary DNS server, which is something else.

[–] [email protected] 2 points 4 months ago (1 children)

Right, we are on the same page but from experience, setting DNS 1 to the pihole and DNS 2 to for example 8.8.8.8 in your DHCP router will make the pihole useless. There are dozens of similar threads across different forums saying the same thing but if you know how to do it please let me know... Example: https://www.reddit.com/r/pihole/comments/864oli/secondary_dns_setting/

[–] [email protected] 0 points 4 months ago (1 children)

Well, after working as some form of systems engineer for the last 17 years, including quite a few where some of my primary responsibilities were looking for DNS servers, this is literally the first time I have come across this.

Also not quite sure what they're doing because my Debian, 2x Windows, 3x Android and occasionally Apple clients never bypass my primary DNS setting. Neither do the server farms I run at work. So who knows.

[–] [email protected] 3 points 4 months ago* (last edited 4 months ago) (1 children)

Yeah, all I could find was vague statements about the DNS server lookup order being "OS specific" and windows specifically being know for "not respecting DNS order", see https://www.reddit.com/r/networking/comments/kb8hvt/dhcp_dns_server_order/

This is also supported by statements from pihole devs: https://www.reddit.com/r/pihole/comments/x2248t/is_it_worth_creating_a_second_pihole_dns_server/ And: https://discourse.pi-hole.net/t/primary-vs-secondary-dns/1536/4

And then there are the hundreds of similar questions which one could take as "evidence by quantity" or whatever.

[–] [email protected] 1 points 4 months ago

In that case I'll be very thankful that mine works as I expect and will try not to change anything.

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