Limit the number of TO/CC/BCC recipients

Apr 12, 2015

I’ve seen on Postfix and Zimbra forums questions about limiting the number of recipients:

Hi, Maybe I’ve missed it but is there a way to limit the number of recipients to prevent users from sending emails to too many recipients at once? Thanks, Mark

Hello Is there an approved way of configuring a maximum number of recipients per message? For example, spammer/salesman tries to email his latest leaflet to every email address he has ever seen - spammer adds 50000 recipients to his email and sends it off. Im pretty sure “smtpd_recipient_limit” in Postfix does this fine, but how to limit only TO field and CC, BCC leave not checked? Thanks for any tips etc!

MSH Traffic Policy

It’s a sophisticated email management system that allows setting server side rules for automatic content control and flow administration. One of the conditions which could be used is the Message Recipients Count condition. It will count recipients in TO, CC or BCC or in all of them.

When a user sends a message with too many recipients the application could:

  • block message
  • move all recipients to BCC field
  • or do one of many other actions…

What else?

This software is for you when you want to:

  • take control over your mail flow
  • append HTML and Plain Text disclaimers
  • check messages for sensitive content (credit cards numbers etc.)
  • manage attachments (add, remove, strip, compress)
  • modify message headers, sender and recipients
  • block unwanted spam
  • create auto replies based on advanced conditions
  • limit number of recipients, attachments, message size, number of sent messages
  • send new and forwarded messages

To learn more visit MSH Traffic Policy website.