About
Strict Transport Security (HSTS) 1) is a header that tells the client that the website should always be contacted with HTTPS
Effect
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.
Management
Set
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
- and submit the website here: https://hstspreload.org/
Delete
In chrome
chrome://net-internals/#hsts
- then delete
