The "Default Spam Rule" has the following recipient and sender information:

to Anyone
And
from Anyone

The "This rule will apply to" option functions as follows:

After selecting one of the options, you will notice that the senders and recipients exceptions are different. The best way to understand this is to choose POP3, since you cannot change the settings there.

Therefore, this option is a wizard for Recipients/Senders settings. IMSS only checks the recipients and senders to decide which rule it is going to use. The rule will apply regardless if incoming or outgoing messages are defined in the menu.

To resolve the issue, you can either create a new spam rule to replace the Default Spam Rule or just edit it to meet your requirements. You can also have two spam rules if necessary.

Here is a sample scenario:

If you have a domain (e.g. mydomain.com) and you want only incoming messages to trigger the rule, then you have to define the recipient and sender:

To *@mydomain.com
And
From Anyone

You need to add the domain name first in the Internal Addresses.

1. In the IMSS web console, go to Policy > Internal Addresses.
2. Add the domain name and then click Save.

   

Now, only the incoming messages will trigger the Default Spam Rule.