Exchange Online Address Book sync between Office 365 tenants

Article
2019-11-27

Question

_{Wednesday, November 27, 2019 12:59 PM}

Hello,

My company is having Exchange online

Recently we acquired two companies and those are running on Exchange online.

We got requirement to share and sync the Exchange online GAL between all three companies (In between 3 Office 365 Tenants), that way users in all three companies can see each other in Outlook.

My question, is there any way we can achieve this by Microsoft available configuration or need to use any third party tool for this?

Sudheesh Surendran

All replies (8)

_{Wednesday, November 27, 2019 7:53 PM | 1 vote}

There's no configuration for this in the O365 suite. What Microsoft offers is the Active Directory Sync service, or in other words MIM as a service: http://aka.ms/adss-demo

Other than that, you could look at third-party tools.

_{Thursday, November 28, 2019 3:06 AM}

Check below discussions,

https://techcommunity.microsoft.com/t5/Microsoft-365/Share-address-book-from-one-to-other-tenants-in-O365/m-p/327036#M2379

https://office365.uservoice.com/forums/273493-office-365-admin/suggestions/10087845-gal-federation-between-different-o365-tenants

https://community.spiceworks.com/topic/1991015-gal-incorporating-several-companies

_{Thursday, November 28, 2019 4:43 AM}

Hi Vasil,

Thanks for the response.

Could you please help me with documentation for ADSS, I could not find anything in Internet.

Appreciate your response.

Thanks,

Sudheesh

Sudheesh Surendran

_{Thursday, November 28, 2019 5:37 AM}

Hi TechSudhi,

It is not feasible to share GAL among Office 365 tenants. And it is not possible to do that (notwithstanding 3rd party apps and services).
You can refer to the article below for more details /en-us/office365/servicedescriptions/exchange-online-service-description/sharing-and-collaboration?redirectedfrom=MSDN

And as Michev mentioned, Microsoft does support sync of multiple on-prem AD forests with one Azure AD if all forests can contact a single Azure AD Connect sync server. See link below for supported topologies /en-us/azure/active-directory/hybrid/plan-connect-topologies

Regards,

Beverly Gao

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_{Thursday, November 28, 2019 9:15 AM}

Hi Vasil,

Thanks for the response.

Could you please help me with documentation for ADSS, I could not find anything in Internet.

Appreciate your response.

Thanks,

Sudheesh

Sudheesh Surendran

There is no documentation, it's a service that Microsoft configures and runs for you, you just ditch some $$ on a monthly basis. Contact your TAM if you are interested in this.

Or use a third-party tool (GalSync).

_{Thursday, November 28, 2019 1:50 PM}

I will check with my TAM for getting this service enabled.

Also could you please help me with some third-party tool available in Market.

I found one in Azure market place "DayOne Collaboration Services.

_{Thursday, November 28, 2019 7:11 PM}

I gave you the tool name above

_{Tuesday, December 3, 2019 10:17 AM}

Just checking in to see if above information was helpful. Please let us know if you would like further assistance.