Good morning

I am not sure if this is possible but what I am trying to acheive is the following:

When an internal user sends and email to a particular internal email address and CC's in an external email address, I want to block that cc'd email to the external address but still allow the email to the internal address to make it through.

Hopefully I have explained this well enough. Is this possible?

Kind regards

Hello

when internal user send to external user /and external address in "TO:" / need allow outgoing?
or need block all outgoing email ?

Hi,

Based on my knowledge, there is no rules to block all messages which are CC to any external email address.

Instead, if you want to block messages which are CC to specific external users such as Mail Contact in Exchange, we can create the following transport rule to have a try:

Please note that this rule would also reject the message sending to recipients which are listed in To filed.

Re

Hi George,

Any updates on this thread?

Regards,