Publishing ADFS Through ISA or TMG Server

To enable single sign-on in Office 365 and a variety of other applications you need to provide a federated authentication system. Microsoft’s free server software for this is currently Active Directory Federation Server 2.0 (ADFS), which is downloaded from Microsoft’s website.

ADFS is installed on a server within your organisation, and a trust (utilising trusted digital certificates) is set up with your partners. If you want to authenticate to the partner system from within your environment it is usual that your application connects to your AFDS server (as part of a bigger process that is better described here: http://blogs.msdn.com/b/plankytronixx/archive/2010/11/05/primer-federated-identity-in-a-nutshell.aspx). But if you are outside of your organisation, or the connection to ADFS is made by the partner rather than the application (and in Office 365 both of these take place) then you either need to install ADFS Proxy or publish the ADFS server through a firewall.

This subject of the blog is how to do this via ISA Server or TMG Server. In addition to configuring a standard HTTPS publishing rule you need to disable Link Translation and high-bit filtering on the HTTP filter to get it to work.

Here are the full steps to set up AFDS inside your organisation and have it published via ISA Server – TMG Server is to all intents and purposes the same, the UI just looks slightly different:

1. New Web Site Publishing Rule. Provide a name.
2. Select the Action (allow).
3. Choose either a single website or load balancer or use ISA’s load balancing feature depending on the number of ADFS servers in your farm.
4. Use SSL to connect:
   
5. Enter the Internal site name (which must be on the SSL certificate on the ADFS server and must be the same as the externally published name as well). Also enter the IP address of the server or configure the HOSTS files on the firewall to resolve this name as you do not want to loop back to the externally resolved name:
   
6. Enter /adfs/* as the path.
7. Enter the ADFS published endpoint as the Public name (which will be subject or SAN on the certificate and will be the same certificate on the ADFS server and the ISA Server):
   
8. Select or create a suitable web listener. The properties of this will include listening on the external IP address that your ADFS namespace resolves to, over SSL only, using the certificate on your ADFS server (exported with private key and installed on ISA Server), no authentication.
9. Allow the client to authenticate directly with the endpoint server:
   
10. All Users and then click Finish.
11. Before you save your changes though, you need to make the following two changes
12. Right-click the rule and select Configure HTTP:
    
13. Uncheck Block high bit characters and click OK.
14. Double-click the rule to bring up its properties and change to the Link Translation tab. Uncheck Apply link translation to this rule:
    
15. Click OK and save your changes.

ADFS should now work through ISA or TMG assuming you have configured ADFS and your partner organisations correctly!

PowerShell Script To Update All UPN’s

This quick script will process all your user accounts in the domain and change the UPN for each of them to a new one, which you need to specify in the script in advance of running it. This script is useful for Office 365 Rich Co-Existence scenarios which require that the UPN (User Principal Name) for each account matches their email address.

Before running the below, add the UPN that you are going to use (your verified vanity domain in Office 365) to Active Directory Domains and Trusts and then copy the below to a text file, saving it as Update-UPN.ps1. Then run this script from an Exchange Management Shell.

$users = Get-User * -ResultSize Unlimited
foreach($user in $users)
{
   $UPN = "$($user.sAMAccountName)@new.upn"
    Write-Host "Setting " $UPN
   $user | Set-User -UserPrincipalName $UPN
}

Tip: Comment out the Write-Host line with # if you do not want feedback on each user changed – it will make the script go much faster

Tip: For testing purposes change the * in the first line to the name of a test user or do something like test* to change all users starting with the word “test” in their username.

Changing ADFS 2.0 Endpoint URL for Office 365

If you are configuring single sign-on for Office 365 then you will need a server running Active Directory Federation Services 2.0 (ADFS 2.0). When you install this you are asked for a URL that acts as an endpoint for the ADFS service, which if you are publishing that endpoint through a firewall such as TMG needs to be on a mutually trusted certificate as either the subject name or alternative subject name.

The documentation uses sts.yourdomain.com which means you need to have this as a valid name of the certificate. I use StartCom SSL, which provide cheap certificates (approx. $100 for as many certificates as you like), but to change a certificate to add an additional alternative subject name requires revoking the current cert, and that comes at additional cost.

So I have a certificate with lots of name on it for my domain, just not sts.mydomain.com so I set about changing the endpoint in ADFS 2.0

Firstly open the ADFS 2.0 administrative console and select the root note:

Click Edit Federation Service Properties in the Action Pane and modify the three values on the General tab:

After clicking OK, restart the AD FS 2.0 Windows Service.

After the restart, create a new Token-Signing Certificate and Token-Decrypting Certificate. These are self signed certificates. To allow you to add these you need to turn off automatic certificate rollover if enabled. This can be done from PowerShell using Set-ADFSProperties –AutoCertificateRollover $false and this cmdlet is available in Windows PowerShell Modules in the Administrative Tools menu.

To update Office 365 start the Microsoft Online Services Module for Windows PowerShell, installed as part of the Office 365 rich co-existence process. In this PowerShell window type Update-MsolFederatedDomain –DomainName yourFederatedDomain.com. You will also need to login to Office 365 in this window first (Connect-MsolService) and set PowerShell with the name of the ADFS server (Set-MsolADFSContext –Computer ADFS_ServerName). Type Get-MsolFederatedDomain –DomainName yourFederatedDomain.com to ensure that the returned URL’s and certificates are correct.

Now its time to update the TMG rule, or create a new one. The listener in TMG must have the same third party certificate and be for HTTPS with the Public Name matching the certificate subject/subject alternative name and the Path value set to /adfs/*. The To page needs to be set with the same URL and internal IP address of the ADFS 2.0 server.

And that should be it – after the Update-MsolFederatedDomain –DomainName yourFederatedDomain.com has completed both sides of the federation trust are aware of the certificate change and automatic login to http://outlook.com/yourFederatedDomain.com should work.