Skip to main content
Email Sharing

SMTP Sharing after Two Companies Merged Part1

SMTP Sharing after Two Companies Merged Part1

Scenario:

Few months ago, our company (CompanyA) merged with another company (CompanyB). Both of them had separate domain forests and exchange environments.The requirement was to have a new company name ComapnyC.com registered and configure the users at both companies to send and receive emails through CompanyC.com domain while keeping their existing domains and exchange functional.
Additionally, only CompanyB should receive emails from the internet, while both CompanyA and CompanyB should be allowed to send emails externally using CompanyC domain in additional to their own domain names while using their existing domains. Finally, they should also be configured to send emails internally. Details about both environments are as follows:
CompanyA
Domain: CompanyA.com
Domain Controllers: Dc1.CompanyA.com, Dc2.CompanyA.com
Exchange Servers
2 Exchange 2013 Mailbox Servers DAG
2 Exchange 2013 CAS Servers NLB
CompanyB
Domain: CompanyB.com
Domain Controllers: Dc1.CompanyB.com, Dc2.CompanyB.com
Exchange Servers
2 Exchange 2010 Mailbox Servers DAG
2 Exchange 2010 Hub/CAS Servers NLB

The solution to the above requirement is to have SMTP sharing, where Domains/Exchange at both companies can share emails for a third domain.

We followed the following steps:

Step by step: 

1. Network connectivity between both sites
2. DNS registration and MX records for new domain (DomainC.com)
3. Configure Accepted Domain for DomainC.com in both environments
4. Create Send and Receive connectors at both sites
5. Work Around for Routing Loops6. Creating Email address policies

In the next article, i will go in the details about each step.

You can check the next article here: SMTP Sharing after Two Companies Merged Part2