Dec 11 2018 12:08 PM
Detecting or avoiding mass/bulk mail messages
From time to time, we have in our Office365 environment, some internal AND external users, sending mail messages to 200 recipients, 400 recipients.
So, some people asked me:
1) There is a way to limit the max number of recipients of a message, like, 30, 50 or 100?
2) There is a way to build a rule, counting the number of recipients, and when someone send a message to, let´s say, 30, 50 100 recipients, this message not be delivered? Particularly import for external users
3) There is a report, to show me messages sent to more than 30, 50, 100 recipients
Dec 11 2018 12:34 PM
Dec 11 2018 12:49 PM
Dec 11 2018 12:52 PM
Dec 11 2018 12:55 PM
Dec 11 2018 12:58 PM
Dec 12 2018 12:05 AM
1) maximum recipients per message is set to 500 in ExO, you cannot change this: https://docs.microsoft.com/en-us/office365/servicedescriptions/exchange-online-service-description/e...
2) No. The only way you can do something like this is via custom transport agents, which are not available in ExO
3) No. Best you can to is harvest the message trace logs for each message and count the number of recipients there, but I haven't seen a ready-to-use solution that does this.
Dec 12 2018 03:06 AM - edited Dec 12 2018 03:09 AM
Thanks ALL!
Yes, i´m not looking into DLs, i´m worried about mass/bulk unsolicited mail.
Sometimes end users select hundreds of people and send messages without thinking about the impact, so we would like to limit and block hundreds of people being copied.
It will be good to have some granular control in transport rules to, for instance, allow only communications department to send those mass/bulk messages, but denying regular users to do it
In the past we had some users sending complaints or doing some personal advertisements (crazy..)