18.104.22.168 is a free Domain Name System (DNS) service. The public DNS service and servers are maintained and owned by Cloudflare in partnership with APNIC. The service functions as a recursive name server providing domain name resolution for any host on the Internet. The service was announced on April 1, 2018, and is claimed by Cloudflare to be "the Internet's fastest, privacy-first consumer DNS service". On August 16, 2018, Cloudflare announced 22.214.171.124 can be used on Android Pie's Private DNS feature using "1dot1dot1dot1.cloudflare-dns.com" hostname. On November 11, 2018, Cloudflare announced a mobile version of their 126.96.36.199 service for Android and iOS.
The 188.8.131.52 DNS service operates recursive name servers for public use at the four following IP addresses. The addresses are mapped to the nearest operational server by anycast routing. The DNS service is also available for Tor clients.
The 184.108.40.206 system uses Knot Resolver software. 
Exposure of abuse
Technology websites noted that by using 220.127.116.11 as the IP address for its service, Cloudflare exposed misconfigurations in existing setups that violated Internet standards (such as RFC1918). 18.104.22.168 was not a reserved IP address, yet was abused by many existing routers (mostly those sold by Cisco Systems) and companies for hosting login pages to private networks, exit pages or other purposes, rendering the proper routing of 22.214.171.124 impossible on those systems. Additionally, 126.96.36.199 is blocked on many networks and by multiple ISPs because the simplicity of the address means that it was previously often used inappropriately for testing purposes and not legitimate use. These previous uses have led to a huge influx of garbage data to Cloudflare's servers.
Cleanup of 188.8.131.52 and 184.108.40.206
The 220.127.116.11/8 IP block was assigned in 2010 to APNIC; before this time it was unassigned space. An unassigned IP space, however is not the same as a reserved IP space for private use (called a reserved IP address). For example, AT&T has said it is working on fixing this issue within its CPE hardware.
Android : 3.8
iOS : 3.12
On April 1, 2019, Cloudflare announced they were planning to launch a VPN service called Warp which would be built into the 18.104.22.168 mobile app. The standard service would be provided for free, with a paid tier which includes additional features. On September 25, 2019, Cloudflare released Warp to the public. 
- APNIC Labs enters into a research agreement with Cloudflare, Geoff Huston, APNIC Blog, April 2, 2018
- Cloudflare launches 22.214.171.124 DNS service that will speed up your internet The Verge, April 1, 2018
- Announcing 126.96.36.199: the fastest, privacy-first consumer DNS service, Official Cloudflare Blog
- Cimpanu, Catalin. "Cloudflare launches Android and iOS apps for its 188.8.131.52 service | ZDNet". ZDNet.
- Setting Up 184.108.40.206 Speed
- Introducing DNS Resolver, 220.127.116.11 (not a joke) DNS resolver, 18.104.22.168, is served by Cloudflare’s Global Anycast Network.
- "Introducing DNS Resolver for Tor". Cloudflare. June 5, 2018. Retrieved October 1, 2018.
- Cherry, Denny (April 5, 2018). "5 reasons Cloudflare's roll-out of 22.214.171.124 has been a disaster". Tech Target. Retrieved April 26, 2018.
- "126.96.36.199: Cloudflare's new DNS attracting 'gigabits per second' of rubbish". ZDNet. April 4, 2018. Retrieved April 26, 2018.
- "1/8 and 27/8 allocated to APNIC". NANOG. January 21, 2010. Retrieved May 3, 2018.
- List of assigned /8 IPv4 address blocks
- Fixing reachability to 188.8.131.52, GLOBALLY!, by Marty Strong, April 10, 2018
- Tweet by @billplein, 3 April 2018
- Khalid, Amrita (April 2, 2019). "Cloudflare's privacy-focused DNS app adds a free VPN". Engadget. Archived from the original on April 2, 2019. Retrieved April 2, 2019.
- Humphries, By Matthew; September 26, 2019 10:18AM EST; September 26, 2019. "Cloudflare Finally Launches Warp, But It's Not a Mobile VPN". PCMAG. Retrieved September 27, 2019.
- Security, Paul Wagenseil 2019-09-26T20:13:55Z. "WARP Promises Faster Speeds on Your Phone Without 5G, but Doesn't Quite Deliver Yet". Tom's Guide. Retrieved September 27, 2019.