HSTS (for Web)

What is HSTS (for Web)?

HSTS (HTTP Strict Transport Security) is a web security policy mechanism that forces browsers to connect to websites over HTTPS instead of HTTP. It protects users from protocol downgrade attacks and cookie hijacking by ensuring that all communication between the browser and the server remains encrypted. HSTS is published as an HTTP header by the web server, instructing browsers to automatically use secure connections in future visits.

Although HSTS is primarily a web protocol, it plays an important role in protecting the broader digital ecosystem, including email-related web applications such as DMARC dashboards, authentication portals, and admin panels.

How HSTS Works

When a website includes the HSTS header, it tells browsers to enforce HTTPS for a specified period. The basic syntax looks like this:

This configuration means:

• max-age=31536000 - The browser must use HTTPS for one year (31,536,000 seconds)
• includeSubDomains - Applies the rule to all subdomains
• preload - Submits the domain to browsers’ built-in preload lists, ensuring HTTPS is enforced from the first visit

Why HSTS Is Important

Without HSTS, users can accidentally connect to insecure HTTP versions of a website, allowing attackers to intercept or modify traffic. HSTS prevents:

• Man-in-the-middle attacks that redirect users to fake login pages
• Session hijacking and cookie theft
• Protocol downgrades where browsers fall back to HTTP

For any organization running authentication portals, analytics dashboards, or customer login pages, HSTS ensures end-to-end encryption and user trust.

HSTS and DMARCeye

While HSTS does not directly affect email authentication, it contributes to the overall trust and security of web-based email systems. DMARCeye adheres to modern web security best practices, including HSTS, to protect sensitive DMARC reporting data and user sessions.

By combining strong HTTPS enforcement with authentication visibility, DMARCeye ensures both safe data handling and comprehensive protection across your entire email infrastructure.

Sign up for a free trial of DMARCeye today and secure your email domain.

To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.