How to add a disclaimer in Exchange 2010

Open Exchange Management Console

Expand Organization Configuration -> Hub Transport -> Transport Rules

Click New Transport Rule from Action Pane (or) You can right click 

 

Fill the Name and Comment

In Conditions applying the scope for Inside the Organization

Appending disclaimer text and using a fallback action if unable to apply

Click finish to complete the process of creating a transport rule for disclaimer

I have tested the rule by sending an email from user1 to user2. It worked successfully as user2 can see the disclaimer text for the email received from user1.