Exchange 2000 has a default limit of 5,000 recipients for a given message. However, this is a flexible limit which can be moved up or down as needed.
Any message with more than the maximum number of recipients will return a non-delivery report to the sender.
Your message did not reach some or all of the intended recipients.
Subject: <subject>
Sent: <time/date>
The following recipient(s) could not be reached:
<recipient list>
The e-mail system limits the number of recipients that can be addressed in a single message. Send the message multiple times to fewer recipients.
<server name> #5.5.3
There are two ways to change the maximum number of recipients per message—either globally, which affects all the mailboxes on the server in question, or on a per-user basis. To change the maximum per-message count globally:
- Open the Exchange System Manager, expand the Global Settings tree, and get the Properties window for Message Delivery.
- Select the Defaults tab and select the Maximum Recipients box under Recipient Limits.
- Type in the maximum number of per-message recipients you want to enforce for the whole system.
To change the maximum per-message count for an individual user:
- Open Active Directory Users and Computers and open the Properties pane for the user account you want to modify.
- Select the Exchange General tab.
- Select Delivery Options.
- Select Maximum Recipients under Recipient Limits and type in the maximum number of recipients you want to enforce for that user.
Keep in mind that the total number of recipients is tallied from entries in both the To, Cc and Bcc fields. Also, every member in a distribution list, whether personal or on a server, is counted as one recipient.
If you suspect that your server is being used as an open message relay (or is being abused by one of your employees), this is another way to prevent unauthorized mass e-mails.
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter. Check out his Windows 2000 blog for his latest advice and musings on the world of Windows network administrators – please share your thoughts as well!
