How to Import the Digital Certificate for the Sender's Root CA into the Trusted Root Certification Authorities Folder in the Local Computer Certificate Store of the Recipient's Exchange Server
This topic explains how to import the digital certificate for the sender's root CA into the Trusted Root Certification Authorities folder in the Local Computer certificate store of the recipient's Exchange server.
Before You Begin
Either at the console or through a terminal session, log on to the recipient's Exchange server using an account that is a member of the local Administrators group.
Procedure
To import the digital certificate for the sender's root CA into the trusted root certification authorities folder in the local computer certificate store of the recipient's Exchange server
Click Start, click Run, type mmc, and then click OK.
Click File, and then click Add/Remove Snap-in.
On the Standalone tab, click Add.
Select Certificates, and then click Add. When prompted, select Computer account, and then click Next.
On the Select Computer page, select Local computer (the computer this console is running on), and then click Finish.
In MMC, expand Certificates – Local Computer, and then expand Trusted Root Certification Authorities.
In the details pane, right-click and point to All tasks, and then click Import.
On the first page of the Certificate Import Wizard, click Next.
In the File name dialog box, type the name and location of the file containing the root CA's digital certificate, and then click Next.
On the Certificate Store page, click Place all certificates in the following store, ensure that the Certificate store dialog box shows Trusted Root Certification Authorities, and then click Next.
On the final page of the wizard, click Finish.
After importing the digital certificate for the sender's root CA, Exchange server will be able to successfully validate the sender's digital certificate on behalf of the recipient.