Alternate UPN suffix across trusted domains

[Office365 Administrator]

Morning all

Quick question (which will probably turn into a long drawn out one).

I have multiple domains, lets call them;

CompanyA.local
CompanyB.local
CompanyC.local

We have a trust between, CompanyA and CompanyB, and CompanyA and CompanyC.

We are migrating to Office365 and we want all users, irrespective of which domain they are members of to have user@CompanyD.com email addresses.

Now, when I have migrated single domains to O365, I have just added an alternate UPN suffix, and changed all users in AD to this suffix.

Now, my question is this.....if I add an alternate UPN suffix of CompanyD.com to all of my domains, will this cause any problems?

Thanks in advance.

Andy

[#2]

Yes you can do that, but you must have only one ADConnect per tenant.

[#3]

Brilliant, thank you.

So, just to confirm, if I install AADSync on CompanyA.local, and set the alternate UPN suffix to CompanyD.com on all domains, I can sync all these domains to Office365?

Andy

[#4 · Accepted solution]

Correct Andy,

Install AD Connect on the CompanyA.local, connect to the other domains also with the setup of AD Connect and setup the UPN on all domains to CompanyD.com.

[#5]

You are a star, thank you :)

[#6]

Hi Nuno Currently we have a single ADConnect server synchronising both the Domains to Office 365. Even though the UPN suffix is added to 1 domain, can I add the same upn suffix on the other domain ??

[#7]

Hi Minesh,

I never tried that scenario, but you could had a the new UPN and change just 1 user to test if it works and fits your needs.