[exim] an ACL snippet

Heya,

I just came out with something like this:

 deny !condition  = ISAUTH
      !senders    = :
      message     = No "Received:" header found in message.
      log_message = No "Received:" header found in message. RCPT: $recipients
      condition   = ${if ={$received_count}{1}}

As far as I know, MTAs are obligated to send "Received:" headers. This
seems to be catching spam not caught otherwise.

Just in case you were interested.