Simple definition
A Distribution List is a mail group that lets a sender deliver the same message to multiple recipients by using a single email address.
Technical definition
In Exchange and Microsoft 365, a distribution list contains members and delivery settings. Its primary purpose is message distribution; unlike a security group, it is not primarily intended to grant permissions to resources.
How it works / role
When a message is sent to the list, the transport service resolves the group, applies any delivery restrictions, and expands the membership so the message can be delivered to the permitted recipients. Lists can be nested and can use sender restrictions or moderation.
What is it used for?
Distribute announcements to a team, department, business population, or any centrally managed set of recipients.
Practical example
An address such as management@example.com contains the management team. A message sent to that address is expanded by the mail service and delivered to each authorized member.
Common issues
- Members are missing or out of date
- Internal or external senders are blocked by delivery restrictions
- Nested groups create loops or excessive expansion
- A distribution list is confused with a Microsoft 365 Group or security group
Key takeaway: A distribution list simplifies message delivery; review its membership, owners, and sender restrictions regularly.