Category: Security

Kernel-mode authentication with a domain account

You may know that kernel-mode authentication is faster then user-mode authentication. You also may know that when you have a webfarm, network service isn’t the “user” you can use for kernel-mode authentication. With thew following command you can configure that the application pool user is used for kernel-mode authentication.

%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/security/authentication/windowsAuthentication -useAppPoolCredentials:true

This wil result in the following configuration in the applicationHost.config

<system.webServer>
   <security>
      <authentication>
         <windowsAuthentication enabled="true" useAppPoolCredentials="true" />
      </authentication>
   </security>
</system.webServer>

You can configure this at the webserver/website/application level.

Which service principal name are registered?

Wanna know if a particular service principal name is registered?

Add the following command to a batch file (called something like “get-spns.bat”) and you get a list of SPN’s registered with a given name and which account is associated with the SPN.

ldifde -f spns.txt -s domaincontroller -r “(|(msDS-AllowedToDelegateTo=*%1*)(servicePrincipalName=*%1*))” -l msDS-AllowedToDelegateTo,servicePrincipalName

usage: get-spns.bat servername/hostheader

open up the created spns.txt and voila.