Using Azure Active Directory for Single Sign On with Yammer
This is a pretty interesting topic that I think is going to be gaining momentum moving forward. As many of you know, when you create a new o365 tenant you automatically get an Azure Active Directory (AAD) instance provisioned for you at the same time. For those of you who have purchased an Enterprise o365 tenant, you now also receive a Yammer network with it (NOTE: I'm not a licensing guy, I can't answer licensing questions, and there are different flavors of tenants and licenses that I can't and won't ever be able to explain). If you're familiar with Yammer, you also know that today it also has its own user directory. We typically will set up directory synchronization from an on premises Active Directory to Yammer to keep the directory up to date. For authentication though, if you want single sign on we usually suggest using ADFS if you're a Windows shop. Going forward though, Azure Active Directory is another alternative you can use.
The main reasons why you would want to use AAD instead of ADFS is one of time and money. If you use ADFS, then you are responsible for building out a highly-available ADFS infrastructure. That will mean 2 or more servers of any number of things: ADFS, ADFS proxy, reverse proxy, firewall, and/or load balancer. That can really add up when you think about the number of servers involved, the cost to acquire OS licenses, and the cost to patch, maintain and operate them. On the other hand, AAD takes care of all of that infrastructure for you, and is included with any o365 tenant. It's free up to about 500k users I think (again - I'm not a licensing guy so check if you are concerned). You can also just create an AAD instance with a regular Azure subscription.
So if you are convinced of the goodness of AAD for this purpose, the good news is getting it set up is relatively straight-forward. The steps you will want to do are:
Add your on premise domain to your o365 subscription.
Go to the o365 Admin pages and click on Domains
Click on Add a Domain
Follow the wizard to add your on premises domain to your o365 tenant
Set up directory synchronization between your on premises Active Directory and o365
Go to the o365 admin pages and click on Users and Groups, then AD synchronization set up
Install AAD module for PowerShell
Activate synchronization in tenant
Install the dirsync tool and run
After dirsync is completed, make at least one on premise user a Global Admin in o365
Run the following PowerShell script using the AAD PS module:
Import-Module MSOnlineExtended -Force
$replyUrl = New-MsolServicePrincipalAddresses –Address "https://saml.yammer.com/sp/ACS.saml2"
New-MsolServicePrincipal –ServicePrincipalNames @("yammer/sso") -DisplayName "Yammer Federation" -Addresses $replyUrl
You should see output afterwards that looks like this:
4. Capture the AppPrincipalID from the output and provide that along with your domain name (i.e. contoso.com) to Yammer support, along with the rest of the documentation they request with the SSO checklist they have at https://success.yammer.com/integrations/single-sign-on/.
You should be good to go at that point, and can do all of your authentication completely in the cloud using AAD.