Refactor MTA-STS policy files: streamline index.html, update mta-sts.txt, and add comprehensive mta-sts.md example file

.well-known/index.html

@@ -3,4 +3,4 @@
 <meta name="robots" content="noindex">
 <title>Redirecting to mta-sts.txt</title>
 <meta http-equiv="refresh" content="0; URL=mta-sts.txt">
-<link rel="canonical" href="mta-sts.txt">
+<link rel="canonical" href="mta-sts.txt">

.well-known/mta-sts.txt

@@ -1,22 +1,5 @@
-# MTA-STS Policy File for lewsion.com
-# For more information, see: https://tools.ietf.org/html/rfc8461
-
 version: STSv1
-# Policy version. Always 'STSv1' as per RFC 8461.
-
 mode: enforce
-# Policy mode. Possible values:
-#   enforce  - Enforce the policy (recommended for production)
-#   testing  - Report violations but do not enforce (use for testing)
-#   none     - Disable MTA-STS
-
 mx: mx1.forwardemail.net
 mx: mx2.forwardemail.net
-# Primary mail server hostname (must match your DNS MX records).
+max_age: 604800
-# Add additional 'mx:' lines for each secondary mail server if needed.
-# Example:
-# mx: mx2.lewsion.com
-
-max_age: 604800
-# Policy lifetime in seconds (e.g., 1209600 = 14 days).
-# Increase for production, decrease for testing.

mta-sts.md

@@ -0,0 +1,46 @@
+# Example: `mta-sts.txt`
+
+This is an example of an **MTA-STS policy file** with all possible values.  
+Save this file as `.well-known/mta-sts.txt` and serve it over HTTPS at:  
+`https://mta-sts.example/.well-known/mta-sts.txt`
+
+---
+
+## Policy Fields
+
+```plaintext
+version: STSv1
+# The version of the MTA-STS policy. Must be "STSv1".
+
+mode: enforce
+# The policy mode. Possible values:
+#   enforce   - SMTP servers must enforce the policy.
+#   testing   - Policy is in testing; violations are reported but not enforced.
+#   none      - No policy is applied.
+
+mx: mail.example.com
+mx: *.mail.example.net
+# The list of MX patterns (hostnames) that are valid for your domain.
+# Wildcards (*) are allowed only as the left-most label.
+
+max_age: 86400
+# The time (in seconds) that the policy is valid for.
+# Recommended minimum is 86400 (1 day). Maximum is 31557600 (1 year).
+```
+
+---
+
+## Example Full Policy
+
+```plaintext
+version: STSv1
+mode: enforce
+mx: mail.example.com
+mx: *.mail.example.net
+max_age: 86400
+```
+
+---
+
+For more details, see:  
+https://datatracker.ietf.org/doc/html/rfc8461