Email Hosting Providers

SPFSPF

SPF Usage Statistics · Download List of All Websites using SPF

The Sender Policy Framework is an open standard specifying a technical method to prevent sender address forgery.

Google Apps for BusinessGoogle Apps for Business

Google Apps for Business Usage Statistics · Download List of All Websites using Google Apps for Business

Web-based email, calendar, and documents for teams. Renamed to Google Apps for Work, but now known as G Suite from Google Cloud.

Business Email Hosting

SSL Certificates

HSTSHSTS

HSTS Usage Statistics · Download List of All Websites using HSTS

Forces browsers to only communicate with the site using HTTPS.

HSTS IncludeSubdomains PreLoadHSTS IncludeSubdomains PreLoad

HSTS IncludeSubdomains PreLoad Usage Statistics · Download List of All Websites using HSTS IncludeSubdomains PreLoad

This website includes instructions for HSTS loading that would allow it to be submitted to the HSTS preload list.

Common Name InvalidCommon Name Invalid

Common Name Invalid Usage Statistics · Download List of All Websites using Common Name Invalid

The Common Name/SAN value of this websites SSL certificate does not correspond to the domain name.

Web Servers

ApacheApache

Apache Usage Statistics · Download List of All Websites using Apache

Apache has been the most popular web server on the Internet since April 1996.