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This happens from time to time with Quad9 DNS. It's annoying since I really like their service. Tonight for about 12 minutes 9.9.9.9 stopped responding. Anyone else experienced this issue with Quad9 before? This is not the first time for me.

#dns #quad9

in reply to steve mookie kong

Quad9, like all the big public recursive DNS services, uses anycast so it might be a regional problem.

There could be BGP announcement flapping, or just a general routing issue. Here's an ASN diagram for Quad9: bgp.tools/prefix/9.9.9.0/24#co…

in reply to steve mookie kong

Could you try to dig with `+tcp` and/or `+nsid` to see what instance is replying correctly and if it works/does not work over TCP.
Is it the same over IPv6? (`dig -6`)
Also try a `traceroute -p 53` (add `-T` for TCP) and compare where your packets go when working/not working.
in reply to Guillaume-Jean Herbiet

@gjherbiet

Neat, will try this next time. Currently while it's working, this is the NSID:

NSID: 72 65 73 37 31 30 2e 70 61 6f 2e 72 72 64 6e 73 2e 70 63 68 2e 6e 65 74 ("res710.pao.rrdns.pch.net")