I have my domain name on DNSimple, my application on Heroku and my name servers on both DNSimple and CloudFlare.
I set up DNSimple so that the first two name servers point to CloudFlare, and the second two point to DNSimple, but often I find that the name servers in DNSimple's UI are reset to all 4 DNSimple name servers.
Also, when I use whatsmydns to track my domain, I see something strange - some servers have the split DNS configuration, some servers have only DNSimple and others have only CloudFlare. It's been like this for several weeks, so it's not a propogation issue.
Any suggestions on how to set this up differently, so that all DNS servers show 2 CloudFlare DNS servers and 2 DNSimple DNS servers?
The main goal for this is to be redundant, incase of a DNS failure, like the one DNSimple suffered a while ago.