Adding One-To-One Mappings <add>


The <add> element of the <oneToOneMappings> element specifies a unique mapping between an individual client certificate and an individual user account.

Note: One-to-one certificate mappings differ from many-to-one certificate mappings, which can map multiple certificates to a single user account.


Version Notes
IIS 7.5 The <add> element was not modified in IIS 7.5.
IIS 7.0 The <add> element of the <oneToOneMappings> element was introduced in IIS 7.0.
IIS 6.0 The <oneToOneMappings> element replaces the IIS 6.0 IIsCertMapper metabase object.


The <iisClientCertificateMappingAuthentication> element is not available on the default installation of IIS 7. To install it, use the following steps.

Windows Server 2008 or Windows Server 2008 R2

  1. On the taskbar, click Start, point to Administrative Tools, and then click Server Manager.
  2. In the Server Manager hierarchy pane, expand Roles, and then click Web Server (IIS).
  3. In the Web Server (IIS) pane, scroll to the Role Services section, and then click Add Role Services.
  4. On the Select Role Services page of the Add Role Services Wizard, select IIS Client Certificate Mapping Authentication, and then click Next.

  5. On the Confirm Installation Selections page, click Install.
  6. On the Results page, click Close.

Windows Vista or Windows 7

  1. On the taskbar, click Start, and then click Control Panel.
  2. In Control Panel, click Programs and Features, and then click Turn Windows Features on or off.
  3. Expand Internet Information Services, then select IIS Client Certificate Mapping Authentication, and then click OK.

How To

There is no user interface for configuring IIS Client Certificate Mapping authentication for IIS 7. For examples of how to configure IIS Client Certificate Mapping authentication programmatically, see the Code Samples section of this document.



Attribute Description
certificate Required string attribute.

Specifies the base64-encoded public certificate from a client certificate. IIS will compare this certificate with the copy of the certificate sent over the internet by a Web client.

The two data strings must be identical for the mapping to proceed. If a client gets another certificate, it will not match the original, even if the copy contains all the same user information as the original. If there are line breaks in the base64-encoded string of the client certificate in this attribute, you must remove them. Line breaks can interfere with the server's ability to compare the server's certificate with the certificate sent by the browser.
enabled Optional Boolean attribute.

Specifies whether the one-to-one mapping is enabled.

The default value is true.
password Optional string attribute.

Specifies the password of the account used to authenticate clients.

Note: To avoid storing unencrypted password strings in configuration files, always use AppCmd.exe to enter passwords. If you use these management tools, the password strings will be encrypted automatically before they are written to the XML configuration files. This provides better password security than storing unencrypted passwords.
username Optional string attribute.

Specifies the user name of the account used to authenticate clients.

Child Elements


Configuration Sample

The following configuration sample enables IIS Client Certificate Mapping authentication using one-to-one certificate mapping for the Default Web Site, creates a singe one-to-one certificate mapping for a user account, and configures the site to require SSL and to negotiate client certificates.

<location path="Default Web Site">
         <access sslFlags="Ssl, SslNegotiateCert" />
            <windowsAuthentication enabled="false" />
            <anonymousAuthentication enabled="false" />
            <digestAuthentication enabled="false" />
            <basicAuthentication enabled="false" />
            <iisClientCertificateMappingAuthentication enabled="true"
                  <add enabled="true"
                     certificate="Base64-Encoded-Certificate-Data" />

How to retrieve Base-64 encoded string from a client certificate

Note: To retrieve a Base-64 encoded certificate data for all of the samples in this topic, you can export a certificate using the following steps:

  • Click Start, then Run.
  • Enter MMC, and then click OK.
  • When the Microsoft Management Console opens, click File, then Add/Remove Snap-ins.
  • In the Add or Remove Snap-ins dialog box:
    • Highlight Certificates in the list of available snap-ins, then click Add.
    • Choose to manage certificates for My user account, then click Finish.
    • Click OK to close the dialog box.
  • In the Microsoft Management Console:
    • Expand Certificates - Current User, then Personal, then Certificates.
    • In the list of certificates, right-click the certificate that you want to export, then click All Tasks, and then click Export.
  • When the Certificate Export Wizard opens:
    • Click Next.
    • Choose No, do not export the private key, then click Next.
    • Choose Base-64 encoded X.509 9 (.CER) for the export format, then click Next.
    • Choose to save the certificate to your desktop as MyCertificate.cer, then click Next.
    • Click Finish; you should see a dialog box that says the export was successful.
  • Close the Microsoft Management Console.
  • Open the MyCertificate.cer file that you exported using Windows Notepad:
    • Remove "-----BEGIN CERTIFICATE-----" from the start of the text.
    • Remove "-----END CERTIFICATE-----" from the end of the text.
    • Concatenate all the lines into a single line of text - this is the Base-64 encoded certificate data that you will use for all of the samples in this topic.

Sample Code

The following code samples enable IIS Client Certificate Mapping authentication using one-to-one certificate mapping for the Default Web Site, create a single one-to-one certificate mapping for a user account, and configure the site to require SSL and to negotiate client certificates.

Note: To retrieve the Base-64 encoded certificate data for the code samples listed below, you can export a certificate using the steps listed in the Configuration Details section of this document.


Note: Because of characters in certificate strings that cannot be parsed by AppCmd.exe, you should not use AppCmd.exe to configure IIS one-to-one certificate mappings.


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 iisClientCertificateMappingAuthenticationSection = config.GetSection("system.webServer/security/authentication/iisClientCertificateMappingAuthentication", "Default Web Site");
         iisClientCertificateMappingAuthenticationSection["enabled"] = true;
         iisClientCertificateMappingAuthenticationSection["oneToOneCertificateMappingsEnabled"] = true;

         ConfigurationElementCollection oneToOneMappingsCollection = iisClientCertificateMappingAuthenticationSection.GetCollection("oneToOneMappings");
         ConfigurationElement addElement = oneToOneMappingsCollection.CreateElement("add");
         addElement["enabled"] = true;
         addElement["userName"] = @"Username";
         addElement["password"] = @"Password";
         addElement["certificate"] = @"Base-64-Encoded-Certificate-Data";

         ConfigurationSection accessSection = config.GetSection("system.webServer/security/access", "Default Web Site");
         accessSection["sslFlags"] = @"Ssl, SslNegotiateCert";



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 iisClientCertificateMappingAuthenticationSection As ConfigurationSection = config.GetSection("system.webServer/security/authentication/iisClientCertificateMappingAuthentication", "Default Web Site")
      iisClientCertificateMappingAuthenticationSection("enabled") = True
      iisClientCertificateMappingAuthenticationSection("oneToOneCertificateMappingsEnabled") = True

      Dim oneToOneMappingsCollection As ConfigurationElementCollection = iisClientCertificateMappingAuthenticationSection.GetCollection("oneToOneMappings")
      Dim addElement As ConfigurationElement = oneToOneMappingsCollection.CreateElement("add")
      addElement("enabled") = True
      addElement("userName") = "Username"
      addElement("password") = "Password"
      addElement("certificate") = "Base-64-Encoded-Certificate-Data"

      Dim accessSection As ConfigurationSection = config.GetSection("system.webServer/security/access", "Default Web Site")
      accessSection("sslFlags") = "Ssl, SslNegotiateCert"

   End Sub

End Module


var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";

var iisClientCertificateMappingAuthenticationSection = adminManager.GetAdminSection("system.webServer/security/authentication/iisClientCertificateMappingAuthentication", "MACHINE/WEBROOT/APPHOST/Default Web Site");
iisClientCertificateMappingAuthenticationSection.Properties.Item("enabled").Value = true;
iisClientCertificateMappingAuthenticationSection.Properties.Item("oneToOneCertificateMappingsEnabled").Value = true;

var oneToOneMappingsCollection = iisClientCertificateMappingAuthenticationSection.ChildElements.Item("oneToOneMappings").Collection;
var addElement = oneToOneMappingsCollection.CreateNewElement("add");
addElement.Properties.Item("enabled").Value = true;
addElement.Properties.Item("userName").Value = "Username";
addElement.Properties.Item("password").Value = "Password";
addElement.Properties.Item("certificate").Value = "Base-64-Encoded-Certificate-Data";

var accessSection = adminManager.GetAdminSection("system.webServer/security/access", "MACHINE/WEBROOT/APPHOST/Default Web Site");
accessSection.Properties.Item("sslFlags").Value = "Ssl, SslNegotiateCert";



Set adminManager = WScript.CreateObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"

Set iisClientCertificateMappingAuthenticationSection = adminManager.GetAdminSection("system.webServer/security/authentication/iisClientCertificateMappingAuthentication", "MACHINE/WEBROOT/APPHOST/Default Web Site")
iisClientCertificateMappingAuthenticationSection.Properties.Item("enabled").Value = True
iisClientCertificateMappingAuthenticationSection.Properties.Item("oneToOneCertificateMappingsEnabled").Value = True

Set oneToOneMappingsCollection = iisClientCertificateMappingAuthenticationSection.ChildElements.Item("oneToOneMappings").Collection
Set addElement = oneToOneMappingsCollection.CreateNewElement("add")
addElement.Properties.Item("enabled").Value = True
addElement.Properties.Item("userName").Value = "Username"
addElement.Properties.Item("password").Value = "Password"
addElement.Properties.Item("certificate").Value = "Base-64-Encoded-Certificate-Data"

Set accessSection = adminManager.GetAdminSection("system.webServer/security/access", "MACHINE/WEBROOT/APPHOST/Default Web Site")
accessSection.Properties.Item("sslFlags").Value = "Ssl, SslNegotiateCert"

Deprecated Elements