How many recipients can be on an SMTP message?
The maximum number of recipients is 5,000 by default. When you send a message from one server to another with 5,000 recipients, you want that message body to be carried across the wire only once. The Windows 2000 SMTP server allows the administrator to specify the maximum number of recipients per message. The intention of having a low number is to make it harder for people to send junk mail to many recipients at once. The SMTP standard specifies that messages with more than 100 recipients should be broken into multiple messages. Note: SMTP standards specify that servers must be able to handle at least 100 recipients.
