Syncing the GAL for Two Companies without GAL Sync

The Acme Construction Company hosts its email in an Office 365 tenant with 550 mailboxes. Acme syncs the GAL to about 500 staff members with iPhones using the CiraSync SaaS solution.

A few months later, Acme acquires Northern Construction, a company that hosts its email on Office 365 and has 160 mailboxes.

You can probably guess what the Acme IT Manager will ask next:

“Will your software sync the GAL of two different Office 365 tenants?”

Companies often need to sync the GAL of two Office 365 tenants. CiraSync does this, but there’s something you should know. We established a perfect GAL Sync solution without actually syncing the two GALs.

How does this intercompany sync work ?

Acme Construction’s email administrator created a new mailbox called “Acme Staff Export” and added it to the GAL target collection. On the next sync task, he also received an ACME GAL contacts folder, as did every smartphone user in the company.

This mailbox, with the [email protected], had a robust password, but no particular permissions; it is not an administrator mailbox.  These credentials can only access this one mailbox.

In the Northern Construction tenant, the email administrator set up the CiraSync dashboard and then  created a new contact list:

They saw this wizard with the different contact source types:

Upon choosing the option “Shared Mailbox of another Company”, they are immediately prompted to provide the email address of the Staff Export mailbox at Acme:

Office 365 Shared Mailbox Remote Tenant

When they click the sign in button, they are presented with a familiar logon prompt from Microsoft:

After they authenticated and granted consent, a new connector was available to navigate to the folders in the Acme staff export mailbox:

After choosing ACME GAL as the source, it is time to select the targets (who gets the ACME GAL). Acme’s IT team clicked All Mailboxes shown at step (A)

After their selection, All Mailboxes appeared as shown in step (B).  This sets up the sync so that everyone in the Northern Construction tenant will get a copy of the Acme GAL. Not everyone had to be targeted. Later on they may build a collection and filter the sync targets.

After they click Next shown at (C), they see the last and final step of the wizard.  It is quite important to set the contact list name (D) as each target contact will have a category set to that name.

Since all of the users at Northern Construction have iPhones, they can safely put contacts in an ACME GAL subfolder (E).

After saving the changes in the final step of the wizard, they use the CiraSync dashboard to run a sync task for the entire Northern tenant. In about one hour, all of the users in Roadrunner Construction have the ACME GAL available on both Outlook, and they iPhones.

They have now completed one half of the GAL to GAL sync. They should first start by pushing the Northern GAL to all Northern smartphone users. Next they would create a [email protected] mailbox and set it as a target of the GAL Sync.  Finally, they would set up a contact list on the ACME tenant to read and the Northern GAL to all ACME users.