Domain configured with Email Forward Only - Spam Filter/BoxTrapper feature

Hi, if we have a domain that is configured with no mailboxes just an email forward from one address to another, does the domain level Spam Filter and BoxTrapper feature filter emails that are being forwarded? Also, it looks like when you create a domain there's a default mailbox created. If you go into that mailbox there is BoxTrapper settings as well. Which Boxtrapper settings effect the mail forwarding if any? Thank you!