What is an Accepted Domain?

Accepted Domain-

An Accepted Domain is a term used primarily in Microsoft Exchange Server (on-premises or Exchange Online in Microsoft 365), and it refers to any domain for which the Exchange organization is responsible for receiving and delivering email.

In Simple Terms:

An Accepted Domain is a domain that your email system (like Microsoft Exchange) accepts email for.


Types of Accepted Domains:

  1. Authoritative Domain:
    • Your organization fully manages all email addresses in this domain.
    • Emails for users in this domain are delivered directly to your Exchange server.
    • Example: You have full control over example.com and host all mailboxes for that domain.
  2. Internal Relay Domain:
    • Your Exchange server accepts email, but forwards it to another mail server within your organization.
    • Useful in hybrid environments or multiple email systems.
    • Example: Email to branch.example.com is accepted, but routed to a different system for final delivery.
  3. External Relay Domain:
    • Your Exchange server accepts mail and relays it to an external system that’s not part of your Exchange organization.
    • Example: Used when transitioning to another mail provider or relaying emails for a partner organization.

Why It Matters:

  • If a domain is not an accepted domain, Exchange will reject email sent to it.
  • It’s critical for organizations with multiple domains or during email migrations.