[exim] Sanity check: ACL to block fake sender addresses

I've noticed that a lot of connections from spammers trying to send mail
to local users claiming the sender is another local user.

So I want to check that if sender domain name is in sender_local_domains
the user must be authenticated or host must be in relay_from_hosts.

Does this look correct?

acl_smtp_mail:
# Accept all authenticated connections
  accept  authenticated = *
# Accept all local hosts
  accept  hosts         = +relay_from_hosts
# Deny if sending host claims to be a local user
  deny    sender_domains = +sender_local_domains
          message       = Fake sender address
# Accept all other
  accept