Microsoft 365 and Destination Control settings

[Chess Norris]

Hello,

I have been asked to help a customer integrate their Microsoft 365 enviroment with Cisco Secure Email and have a question on how to use Desination Control.

When reading the guide Configure Microsoft 365 with Secure Email they mention that we should Impose a self-throttle to a delivery domain in your Destination Controls to avoid any throttling done by Microsoft due to the domains unknown reputation.

In the guide they are using a maximum of 10 concurrent connections and maximum 20 messages per connection, but I belive this is an example more than a recomendation? 

The default destination limit settings are 500 concurrent connections and 50 messages per connection, but I know that for example Gmail have limits on how many messages they allow.

Is there similair limitations when sending emails to domains hosted on Microsoft 365 or is that someting the customer can adjust themself? 

What are other peoples using for settings?

Thanks

/Chess 

[Ken Stieers · Accepted solution]

You're correct that it's a recommendation. You could probably get away with more. Again the point is to let MS figure out its legit before opening the pipe (assuming you actually have enough email flow to throw alarms.)
I haven't found the docs on what MS will accept inbound for a domain... gut feel, they just take it all and deal with the load by throwing more resources at it.

[Chess Norris]

Thanks for the reply. That's really helpful.

Best regards

/Chess