cf worker can monitor your api or w/e and update dns record with relevant ip in case of failure

or as free solution use Cloudflare quasi-roundrobin DNS - multiple A records can route visitors, in case one doesn't respond.

Is it possible to create a Failover DNS with CloudFlare Worker?

To save your time, use cloudns.net.

You'll need something to check how the servers are doing (up? down?) and to tell the DNS provider's API (or your own servers) which one to use.

For DNS in particular, if you like trying to run things yourself (e.g. to learn), you can use PowerDNS with Lua records: https://doc.powerdns.com/authoritative/lua-records/. You can use the ifportup f

If I have 2 servers that are almost identical and I need the second server to be used in the event that the second goes down I believe that is called fail over DNS.

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And in any case I have to change DNS and rDNS?

* rDNS update

Not sure why it's even asking for this on the first step in the process, as there's approximately 0 chance I'd move my DNS from where it's been for the last 15 years to some random VPS.

personal sites, blogs or other webservices. 3 DNS servers. One VPS is nothing but a VPN hub, handling all the routing for the internal IPv6 net that every VPS is connected to via a wireguard network.

73.20 Mbit/s 70.694 ms Germany, Berlin (DNS:NET) 110.62 Mbit/s 437.11 Mbit/s 74.911 ms Germany, Munich (InterNetX) 109.21 Mbit/s 388.08 Mbit/s 71.019 ms Denmark, Copen

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* adguard home dns (f.ck ads)

As Francisco said, commonly abused domain for DNS amplification due to its large RRSIG response size (>10k bytes)

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It's a very common DNS amplification domain that gets abused.

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@InceptionHosting could you give a little more details as to what is complimentary ddos protection? Interested in getting 2 of these from you to serve dns.