Our spam filter can test incoming e-mail to determine whether or not it looks like spam.
Additionally, Greylisting is a highly effective method at stopping spam and viruses from being delivered to your mailbox. You can apply greylist settings on a domain level.
You can also use Whitelisting. When you use auto whitelisting, the server remembers the addresses you send mail to and will direct replies from these addresses directly to your inbox for a period of seven days -- bypassing your server's spam filters entirely.