HTTP - Strict Transport Security (HSTS) - mandatory HTTPS


Strict Transport Security (HSTS) is a header that tells the client that the website should always be contacted with HTTPS


When HSTS is on, if it's not possible to make a https connection (for instance if the certificate is not valid), the user will not be able to navigate the website and will get this message.



Recommended value:

Strict-Transport-Security: max-age=31536000; includeSubDomains

Example in Apache The Apache htaccess file with Apache - HTTP Header (mod_header module)

Header set Strict-Transport-Security "max-age=63072000; includeSubDomains"

Hardcoded in chrome (preload)

To submit domains for hard coded inclusion in Chrome's HTTP Strict Transport Security (HSTS) preload list:

  • Add the preload tag to the value
Strict-Transport-Security: max-age=63072000; includeSubDomains; preload


In chrome

  • then delete

Documentation / Reference

Powered by ComboStrap