Limit the number of TO/CC/BCC recipients

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

Hi, Maybe I’ve missed it but is there a way to limit the amount of recipients to prevent users to sent 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 to set server side rules for automatic content control and flow administration. One of the condition which could be used is Messsage Recipients Count condition. It will count recipients in TO, CC or BCC or in all of them.

When user sent message with too many recipients 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 you 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
  • sent new and forwarded messages

To learn more visit MSH Traffic Policy website.

Łukasz is a software developer and owner of MSH Software company which builds email processing tools for Microsoft Exchange, Zimbra Collaboration Suite and Postfix. He specializes in server, desktop and web applications written in Java, .NET and C++.