Best way in asp.net to force https for an entire site?

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About 6 months ago I rolled out a site where every request needed to be over https. The only way at the time I could find to ensure that every request to a page was over https was to check it in the page load event. If the request was not over http I would response.redirect("https://example.com")

Is there a better way -- ideally some setting in the web.config?

15 Answers

Please use HSTS (HTTP Strict Transport Security)

from http://www.hanselman.com/blog/HowToEnableHTTPStrictTransportSecurityHSTSInIIS7.aspx

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="HTTP to HTTPS redirect" stopProcessing="true">
                    <match url="(.*)" />
                    <conditions>
                        <add input="{HTTPS}" pattern="off" ignoreCase="true" />
                    </conditions>
                    <action type="Redirect" url="https://{HTTP_HOST}/{R:1}"
                        redirectType="Permanent" />
                </rule>
            </rules>
            <outboundRules>
                <rule name="Add Strict-Transport-Security when HTTPS" enabled="true">
                    <match serverVariable="RESPONSE_Strict_Transport_Security"
                        pattern=".*" />
                    <conditions>
                        <add input="{HTTPS}" pattern="on" ignoreCase="true" />
                    </conditions>
                    <action type="Rewrite" value="max-age=31536000" />
                </rule>
            </outboundRules>
        </rewrite>
    </system.webServer>
</configuration>

Original Answer (replaced with the above on 4 December 2015)

basically

protected void Application_BeginRequest(Object sender, EventArgs e)
{
   if (HttpContext.Current.Request.IsSecureConnection.Equals(false) && HttpContext.Current.Request.IsLocal.Equals(false))
   {
    Response.Redirect("https://" + Request.ServerVariables["HTTP_HOST"]
+   HttpContext.Current.Request.RawUrl);
   }
}

that would go in the global.asax.cs (or global.asax.vb)

i dont know of a way to specify it in the web.config

The IIS7 module will let you redirect.

    <rewrite>
        <rules>
            <rule name="Redirect HTTP to HTTPS" stopProcessing="true">
                <match url="(.*)"/>
                <conditions>
                    <add input="{HTTPS}" pattern="^OFF$"/>
                </conditions>
                <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="SeeOther"/>
            </rule>
        </rules>
    </rewrite>

If you are unable to set this up in IIS for whatever reason, I'd make an HTTP module that does the redirect for you:

using System;
using System.Web;

namespace HttpsOnly
{
    /// <summary>
    /// Redirects the Request to HTTPS if it comes in on an insecure channel.
    /// </summary>
    public class HttpsOnlyModule : IHttpModule
    {
        public void Init(HttpApplication app)
        {
            // Note we cannot trust IsSecureConnection when 
            // in a webfarm, because usually only the load balancer 
            // will come in on a secure port the request will be then 
            // internally redirected to local machine on a specified port.

            // Move this to a config file, if your behind a farm, 
            // set this to the local port used internally.
            int specialPort = 443;

            if (!app.Context.Request.IsSecureConnection 
               || app.Context.Request.Url.Port != specialPort)
            {
               app.Context.Response.Redirect("https://" 
                  + app.Context.Request.ServerVariables["HTTP_HOST"] 
                  + app.Context.Request.RawUrl);    
            }
        }

        public void Dispose()
        {
            // Needed for IHttpModule
        }
    }
}

Then just compile it to a DLL, add it as a reference to your project and place this in web.config:

 <httpModules>
      <add name="HttpsOnlyModule" type="HttpsOnly.HttpsOnlyModule, HttpsOnly" />
 </httpModules>

In IIS10 (Windows 10 and Server 2016), from version 1709 onwards, there is a new, simpler option for enabling HSTS for a website.

Microsoft describe the advantages of the new approach here, and provide many different examples of how to implement the change programmatically or by directly editing the ApplicationHost.config file (which is like web.config but operates at the IIS level, rather than individual site level). ApplicationHost.config can be found in C:\Windows\System32\inetsrv\config.

I've outlined two of the example methods here to avoid link rot.

Method 1 - Edit the ApplicationHost.config file directly Between the <site> tags, add this line:

<hsts enabled="true" max-age="31536000" includeSubDomains="true" redirectHttpToHttps="true" />

Method 2 - Command Line: Execute the following from an elevated command prompt (i.e. right mouse on CMD and run as administrator). Remember to swap Contoso with the name of your site as it appears in IIS Manager.

c:
cd C:\WINDOWS\system32\inetsrv\
appcmd.exe set config -section:system.applicationHost/sites "/[name='Contoso'].hsts.enabled:True" /commit:apphost
appcmd.exe set config -section:system.applicationHost/sites "/[name='Contoso'].hsts.max-age:31536000" /commit:apphost
appcmd.exe set config -section:system.applicationHost/sites "/[name='Contoso'].hsts.includeSubDomains:True" /commit:apphost
appcmd.exe set config -section:system.applicationHost/sites "/[name='Contoso'].hsts.redirectHttpToHttps:True" /commit:apphost

The other methods Microsoft offer in that articles might be better options if you are on a hosted environment where you have limited access.

Keep in mind that IIS10 version 1709 is available on Windows 10 now, but for Windows Server 2016 it is on a different release track, and won't be released as a patch or service pack. See here for details about 1709.

I spent sometime looking for best practice that make sense and found the following which worked perfected for me. I hope this will save you sometime.

Using Config file (for example an asp.net website) https://blogs.msdn.microsoft.com/kaushal/2013/05/22/http-to-https-redirects-on-iis-7-x-and-higher/

or on your own server https://www.sslshopper.com/iis7-redirect-http-to-https.html

[SHORT ANSWER] Simply The code below goes inside

<system.webServer> 
 <rewrite>
     <rules>
       <rule name="HTTP/S to HTTPS Redirect" enabled="true" 
           stopProcessing="true">
       <match url="(.*)" />
        <conditions logicalGrouping="MatchAny">
        <add input="{SERVER_PORT_SECURE}" pattern="^0$" />
       </conditions>
       <action type="Redirect" url="https://{HTTP_HOST}{REQUEST_URI}" 
        redirectType="Permanent" />
        </rule>
       </rules>
 </rewrite>
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