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HSTS Settings for a Web Site <hsts>

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Overview

The <hsts> element of the <site> element contains attributes that allow you to configure HTTP Strict Transport Security (HSTS) settings for a site on IIS 10.0 version 1709 and later.

Note

If the <hsts> element is configured in both the <siteDefaults> section and in the <site> section for a specific site, the configuration in the <site> section is used for that site.

Compatibility

Version Notes
IIS 10.0 version 1709 The <hsts> element of the <site> element was introduced in IIS 10.0 version 1709.
IIS 10.0 N/A
IIS 8.5 N/A
IIS 8.0 N/A
IIS 7.5 N/A
IIS 7.0 N/A
IIS 6.0 N/A

Setup

The <hsts> element of the <site> element is included in the default installation of IIS 10.0 version 1709 and later.

How To

There is no user interface that lets you configure the <hsts> element of the <site> element for IIS 10.0 version 1709. For examples of how to configure the <hsts> element of the <site> element programmatically, see the Sample Code section of this document.

Configuration

Attributes

Attribute Description
enabled Optional Boolean attribute.

Specifies whether HSTS is enabled (true) or disabled (false) for a site. If HSTS is enabled, the Strict-Transport-Security HTTP response header is added when IIS replies an HTTPS request to the web site.

The default value is false.
max-age Optional uint attribute.

Specifies the max-age directive in the Strict-Transport-Security HTTP response header field value.

The default value is 0.
includeSubDomains Optional Boolean attribute.

Specifies whether the includeSubDomains directive is included in the Strict-Transport-Security HTTP response header field value.

Note: Enable this attribute only if all subdomains indeed offer HTTP-based service over TLS/SSL.

The default value is false.
preload Optional Boolean attribute.

Specifies whether the preload directive is included in the Strict-Transport-Security HTTP response header field value.

Note: Enable this attribute only if the domain of the site has been submitted for inclusion in the HSTS preload list.

The default value is false.
redirectHttpToHttps Optional Boolean attribute.

Specifies whether HTTP to HTTPS redirection is enabled (true) or disabled (false) for a site.

Note: Enabling redirectHttpToHttps enforces the site-level HTTP to HTTPS redirection. When IIS redirects an HTTP request, it replaces the URI scheme with "https" and ignores the port component. Make sure that the redirection destination provides HTTP-based service over TLS/SSL on standard port 443.

The default value is false.

Child Elements

None.

Configuration Sample

The following configuration sample shows a web site named Contoso that has HSTS enabled with both HTTP and HTTPS bindings. The max-age attribute is set as 31536000 seconds (a year) so that the user agents will regard the host as a Known HSTS Host within a year after the reception of the Strict-Transport-Security header field. The includeSubDomains attribute is set as true to specify that the HSTS policy applies to this HSTS Host (contoso.com) as well as any subdomain (for example, www.contoso.com or marketing.contoso.com). Finally, the redirectHttpToHttps attribute is set as true so that all HTTP requests to the site will be redirected to HTTPS.

<site name="Contoso" id="1">
    <application path="/" applicationPool="Contoso">
        <virtualDirectory path="/" physicalPath="C:\Contoso\Content" />
    </application>
    <bindings>
        <binding protocol="http" bindingInformation="*:80:contoso.com" />
        <binding protocol="https" bindingInformation="*:443:contoso.com" sslFlags="0" />
    </bindings>
    <hsts enabled="true" max-age="31536000" includeSubDomains="true" redirectHttpToHttps="true" />
</site>

Sample Code

The following code samples enable HSTS for a web site named Contoso with both HTTP and HTTPS bindings. The sample sets max-age attribute as 31536000 seconds (a year), and enables both the includeSubDomains and the redirectHttpToHttps attributes.

AppCmd.exe

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

Note

You must be sure to set the commit parameter to apphost when you use AppCmd.exe to configure these settings. This commits the configuration settings to the appropriate location section in the applicationHost.config file.

C#

using System;
using System.Text;
using Microsoft.Web.Administration;

internal static class Sample
{
    private static void Main()
    {
        using(ServerManager serverManager = new ServerManager())
        { 
            Configuration config = serverManager.GetApplicationHostConfiguration();
            ConfigurationSection sitesSection = config.GetSection("system.applicationHost/sites");
            ConfigurationElementCollection sitesCollection = sitesSection.GetCollection();
            
            ConfigurationElement siteElement = FindElement(sitesCollection, "site", "name", @"Contoso");
            if (siteElement == null) throw new InvalidOperationException("Element not found!");

            ConfigurationElement hstsElement = siteElement.GetChildElement("hsts");
            hstsElement["enabled"] = true;
            hstsElement["max-age"] = 31536000;
            hstsElement["includeSubDomains"] = true;
            hstsElement["redirectHttpToHttps"] = true;

            serverManager.CommitChanges();
        }
    }
    
    private static ConfigurationElement FindElement(ConfigurationElementCollection collection, string elementTagName, params string[] keyValues)
    {
        foreach (ConfigurationElement element in collection)
        {
            if (String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase))
            {
                bool matches = true;
                for (int i = 0; i < keyValues.Length; i += 2)
                {
                    object o = element.GetAttributeValue(keyValues[i]);
                    string value = null;
                    if (o != null)
                    {
                        value = o.ToString();
                    }
    
                    if (!String.Equals(value, keyValues[i + 1], StringComparison.OrdinalIgnoreCase))
                    {
                        matches = false;
                        break;
                    }
                }
                if (matches)
                {
                    return element;
                }
            }
        }
        return null;
    }
}

VB.NET

Imports System
Imports System.Text
Imports Microsoft.Web.Administration

Module Sample

   Sub Main()
      Dim serverManager As ServerManager = New ServerManager
      Dim config As Configuration = serverManager.GetApplicationHostConfiguration
      Dim sitesSection As ConfigurationSection = config.GetSection("system.applicationHost/sites")
      Dim sitesCollection As ConfigurationElementCollection = sitesSection.GetCollection

      Dim siteElement As ConfigurationElement = FindElement(sitesCollection, "site", "name", "Contoso")
      If (siteElement Is Nothing) Then
         Throw New InvalidOperationException("Element not found!")
      End If

      Dim hstsElement As ConfigurationElement = siteElement.GetChildElement("hsts")
      hstsElement("enabled") = True
      hstsElement("max-age") = 31536000
      hstsElement("includeSubDomains") = True
      hstsElement("redirectHttpToHttps") = True

      serverManager.CommitChanges()
   End Sub

   Private Function FindElement(ByVal collection As ConfigurationElementCollection, ByVal elementTagName As String, ByVal ParamArray keyValues() As String) As ConfigurationElement
      For Each element As ConfigurationElement In collection
         If String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase) Then
            Dim matches As Boolean = True
            Dim i As Integer
            For i = 0 To keyValues.Length - 1 Step 2
               Dim o As Object = element.GetAttributeValue(keyValues(i))
               Dim value As String = Nothing
               If (Not (o) Is Nothing) Then
                  value = o.ToString
               End If
               If Not String.Equals(value, keyValues((i + 1)), StringComparison.OrdinalIgnoreCase) Then
                  matches = False
                  Exit For
               End If
            Next
            If matches Then
               Return element
            End If
         End If
      Next
      Return Nothing
   End Function

End Module

JavaScript

var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";
var sitesSection = adminManager.GetAdminSection("system.applicationHost/sites", "MACHINE/WEBROOT/APPHOST");
var sitesCollection = sitesSection.Collection;

var siteElementPos = FindElement(sitesCollection, "site", ["name", "Contoso"]);
if (siteElementPos == -1) throw "Element not found!";
var siteElement = sitesCollection.Item(siteElementPos);

var hstsElement = siteElement.ChildElements.Item("hsts");
hstsElement.Properties.Item("enabled").Value = true;
hstsElement.Properties.Item("max-age").Value = 31536000;
hstsElement.Properties.Item("includeSubDomains").Value = true;
hstsElement.Properties.Item("redirectHttpToHttps").Value = true;

adminManager.CommitChanges();

function FindElement(collection, elementTagName, valuesToMatch)
{
    for (var i = 0; i < collection.Count; i++)
    {
        var element = collection.Item(i);
        if (element.Name == elementTagName)
        {
            var matches = true;
            for (var iVal = 0; iVal < valuesToMatch.length; iVal += 2)
            {
                var property = element.GetPropertyByName(valuesToMatch[iVal]);
                var value = property.Value;
                if (value != null)
                {
                    value = value.toString();
                }
                if (value != valuesToMatch[iVal + 1])
                {
                    matches = false;
                    break;
                }
            }
            if (matches)
            {
                return i;
            }
        }
    }
    
    return -1;
}

VBScript

Set adminManager = WScript.CreateObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"
Set sitesSection = adminManager.GetAdminSection("system.applicationHost/sites", "MACHINE/WEBROOT/APPHOST")
Set sitesCollection = sitesSection.Collection
siteElementPos = FindElement(sitesCollection, "site", Array("name", "Contoso"))

If siteElementPos = -1 Then
   WScript.Echo "Element not found!"
   WScript.Quit
End If

Set siteElement = sitesCollection.Item(siteElementPos)
Set hstsElement = siteElement.ChildElements.Item("hsts")
hstsElement.Properties.Item("enabled").Value = True
hstsElement.Properties.Item("max-age").Value = 31536000
hstsElement.Properties.Item("includeSubDomains").Value = True
hstsElement.Properties.Item("redirectHttpToHttps").Value = True

adminManager.CommitChanges()

Function FindElement(collection, elementTagName, valuesToMatch)
   For i = 0 To CInt(collection.Count) - 1
      Set element = collection.Item(i)
      If element.Name = elementTagName Then
         matches = True
         For iVal = 0 To UBound(valuesToMatch) Step 2
            Set property = element.GetPropertyByName(valuesToMatch(iVal))
            value = property.Value
            If Not IsNull(value) Then
               value = CStr(value)
            End If
            If Not value = CStr(valuesToMatch(iVal + 1)) Then
               matches = False
               Exit For
            End If
         Next
         If matches Then
            Exit For
         End If
      End If
   Next
   If matches Then
      FindElement = i
   Else
      FindElement = -1
   End If
End Function

IISAdministration PowerShell Cmdlets

Import-Module IISAdministration
Reset-IISServerManager -Confirm:$false
Start-IISCommitDelay

$sitesCollection = Get-IISConfigSection -SectionPath "system.applicationHost/sites" | Get-IISConfigCollection
$siteElement = Get-IISConfigCollectionElement -ConfigCollection $sitesCollection -ConfigAttribute @{"name"="Contoso"}
$hstsElement = Get-IISConfigElement -ConfigElement $siteElement -ChildElementName "hsts"
Set-IISConfigAttributeValue -ConfigElement $hstsElement -AttributeName "enabled" -AttributeValue $true
Set-IISConfigAttributeValue -ConfigElement $hstsElement -AttributeName "max-age" -AttributeValue 31536000
Set-IISConfigAttributeValue -ConfigElement $hstsElement -AttributeName "includeSubDomains" -AttributeValue $true
Set-IISConfigAttributeValue -ConfigElement $hstsElement -AttributeName "redirectHttpToHttps" -AttributeValue $true

Stop-IISCommitDelay
Remove-Module IISAdministration