What happens if my dog attacks the mailman?

I let my dog outside the backyard to bring him into the house through the side door, and he goes after the mailman (whom I did not see). The mailman yells to get the dog away from him, and he sounds pretty mad. I grab my dog and scold him, bringing him inside. My dog did NOT bite the mailman, however. Is there a chance he will press charges/fine us?