Microsoft Exchange Server 2013: Mailbox and High Availability

Mail users

Mail users are much like contacts in that both object types have external email addresses. However, there is one important difference. Contacts are usually linked to people who have no relationship with your organization, but mail users are linked to Active Directory accounts. You can therefore think of mail contacts as being most suitable for people who work outside your company, whereas mail users are often the most appropriate choice for those who work inside the company.

Inside Out Mail users and security groups

In essence, Exchange supports this recipient type to enable you to incorporate users in the GAL even when they use a different email system. Because mail users are linked to Active Directory accounts, they also are security ...