We were using Cloudflare’s 220.127.116.11 as our DNS servers for our network and everything has been working fine for months. This morning we came in to work and the network could not reach any domain names (amazon.com, google.com, etc…). Our camera system & voip phones were working since they use a static IP.
We tracked the issue down to Cloudflare’s DNS not being reachable by the network, so it wasn’t resolving any domains.
I changed the DNS servers to use Google’s 18.104.22.168 and everything started working fine.
Why might this have happened? Where we blocked by Cloudflare and if so, how to do we confirm that and appeal it.