There are several ways to limit the sending of mass emails via an SMTP server:
1. Set a maximum limit on the number of recipients per message – This will prevent users from sending out large amounts of emails at once.
1. Implement rate limiting – This means limiting the number of emails that can be sent in a certain time period. For example, you can limit the number of emails that can be sent per minute or hour.
1. Verify email addresses – Verify that the email addresses being sent to are valid and active. This can prevent bounces and reduce the number of emails being sent to non-existent addresses.
1. Implement anti-spam measures – By implementing anti-spam measures such as SPF, DKIM, and DMARC, you can reduce the likelihood of your messages being flagged as spam and prevent them from being sent.
1. Monitor email traffic – Keep an eye on email traffic and usage patterns to detect any unusual behavior, such as a sudden spike in email volume, which could indicate a mass email campaign.
