CloudFlare - Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable.
Amazon Route 53 - Amazon Route 53 is a highly available and scalable DNS web service.
Myra Security - The Myra Security-as-a-Service platform monitors, analyzes, and filters malicious internet traffic before virtual attacks can do any real harm.
GoDaddy DNS - GoDaddy DNS helps manage website performance, reliability and security.
Altospam - Antispam and antivirus software on Cloud
DNSimple - Domain Name Service with low cost hosted DNS, an easy to use web interface, and a REST API for automation. Hosting DNS has never been so simple.