Spam Filtering and then Forwarding Email

I have some users with addresses in my domain that are just email aliases for their ‘real’ email addresses. This results in my server forwarding a lot of spam. I would like to spam filter the email that my server forwards.

Will I have to convert alias addresses to pop accounts in order to do this? Can I create a pop account for which incoming mail is spam filtered and non-spam is then automatically forwarded to another address?

Yeah, Spam is only processed on addresses that have actual system accounts (ie, POP and IMAP users).

Sure, you convert those aliases into POP/IMAP accounts – but at that point, you’ll be spam checking email both there, and at the address you forward to, so I’m not sure you’d be gaining much.

But you could certainly do that if you wanted :slight_smile:

The reason I would want to filter spam and then forward to an address at which there might also be a spam filter is that I do not want the servers that receive forwarded message to start treating or reporting my server as a spam source.

The problem is that the spam filtering stack happens during delivery to a local mailbox (via procmail). The next version of Virtualmin introduces greylisting policy support, which will filter some spam.

If you want comprehensive spam filtering of forwarded mail, you will need to run a content filter. Something like amavisd-new. This means the per-user and per-domain features of Virtualmin are lost, but it does perform spam/AV scanning before mail gets forwarded.

So does this mean that if I

  1. replace an alias address with a new user and mailbox,

  2. under Edit Mail and FTP Users select the new user,

  3. on the resulting ‘Edit Mailbox’ page under ‘Mail forwarding settings’ I check ‘Forward to other addresses’ and enter a forwarding address in the text box below that checkbox

the forwarded mail will not be spam filtered?