For your .NET Website, this is the simple way below, just update your web.config with the following:
<system.webServer>
<httpProtocol>
<customHeaders>
<add name="Strict-Transport-Security" value="max-age=31536000" />
</customHeaders>
</httpProtocol>
<rewrite>
<rules>
<rule name="HTTPS force" enabled="true" stopProcessing="true">
<match url="(.*)" />
<conditions>
<add input="{HTTPS}" pattern="^OFF$" />
</conditions>
<action type="Redirect" url="https://{HTTP_HOST}{REQUEST_URI}" redirectType="Permanent" />
</rule>
</rules>
</rewrite>
</system.webServer>
</system.webServer>
If you want to do it with IIS 8
- Open IIS 8
- Click “Add Rule(s)”
- Blank rule
- Name: HSTS Redirect
- Requested URL: Matches the Pattern
- Using: Regular Expressions
- Pattern: (.*)
- Ignore case: Checked
Conditions
- Logical grouping: Match all
- Click “Add”
- Condition input: {HTTPS}
- Check if input string: Matches the Pattern
- Pattern: ^OFF$
- Ignore case: Checked
Action
- Action type: Redirect
- Redirect URL: https://{HTTP_HOST}/{R:1}
- Append query string: Checked
- Redirect type: Permanent (301)