Does Microsoft Support Multiple ADFS Instances on One AD Domain?

Recently I was working on a SharePoint project for a client with offices throughout the globe, with key offices in UK, North America and Australia.

They had one SharePoint environment in each region.

For the Australian SharePoint farm we wanted to start authenticating users via ADFS.

Our client’s only ADFS environment was in the UK though and one of the key concerns I had was how long it would take to authenticate users to the UK given the high network latency, and the fact that there is pretty much nothing that can be done about the latency.

One option that I wanted to explore was standing up a new ADFS environment locally within Australia, however there was some doubt was to whether Microsoft actually supported having more than one ADFS environment connected to the same AD DS domain.

I checked with my colleagues and they confirmed that it would work fine, but the key question was still… does Microsoft support this scenario?

So I contacted Microsoft Support and as expected (though to my pleasure I now had something official) this was the response:

“Yes Microsoft supports multiple ADFS farms in one domain in different sites. So if the environment matches the below conditions then only it will work in multiple ADFS farm scenario:”

1. The service names for ADFS farms should be different for each site (location)
2. You cannot federate same application with two farms in the same domain. i.e. the ADFS farms should be configured with different applications.
3. You can have only one ADFS farm in a site (location).