From: https://old.reddit.com/r/firefox/comments/1eeosb5/cloudflare_dns_as_default_dns_can_be_bad_or_good/
WARNING: This article has a lot of advanced knowledges.
- First, everyone needs to understand that by default, Firefox is using Cloudflare as default DNS provider.
- And Firefox is using DoH (DNS-over-HTTPS).
- DoH is the current slowest DNS implementation, much slower than plain DNS, DNS-over-TLS and DNS-over-QUIC.
- Advantages of DoH/DoT/DoQ is, they can bypass censorships, so you can surf ISP blocked websites.
- Cloudflare DNS is only good for American, because this DNS doesn't have [ECS](https://community.akamai.com/customers/s/article/What-is-ECS-EDNS0-Client-Subnet?language=en_US), so people living from for example Japan will always use CDNs from USA, for example Youtube's servers are all over the world, and there's servers from Japan to serve Japanese, but using servers from USA will slow down everything because of lantecy. **Basically, it can't find closest CDNs for users from outside the USA.**
Unlike Firefox, by default Chrome is using System DNS, which is plain DNS, this is the fastest and "always work" in 99% cases because the System DNS will likely to use ISP DNS, which automatically makes use of ECS-like to find closest CDNs eventhough this is unsecure, because ISP DNS is country level DNS, it always find closest CDNs.
I think Firefox really wants to reconsider about making Cloudflare DoH as default, this is NOT good for non-American.
