[Exim] ACL's RULE!

I just threw these together as part of an acl_data..

I obviously havent had much time to test them, but they should be pretty
effective at blocking mail with senders forged in any of these domains..

I release these under the terms of the GPL ;) (In other words, use them
all you want. If you find a way to make them better, mail your changes
back to the exim list)

# All hotmail.com mail should have this header
  deny          sender_domains  = hotmail.com
                message         = X-Forgery: NOT HOTMAIL
                condition       = ${if def:header_X-Originating-IP:{no}{yes}}

# All aol.com mail should have this header
  deny          sender_domains  = aol.com
                message         = X-Forgery: NOT AOL MAILER
                condition       = ${if match {$h_X-Mailer:}{.*[Aa][Oo][Ll].*} {no}{yes}}

# All aol.com mail should have a matching received header
  deny          sender_domains  = aol.com
                message         = X-Forgery: NOT AOL SERVER
                condition       = ${if match {$h_Received:}{.*by.*[Aa][Oo][Ll]\.[Cc][Oo][Mm].*}{no}{yes}}

# All yahoo.com mail will have either
# "...yahoo.com via HTTP "
# *OR*
# "...yahoo.com with NNFMP"

  deny          sender_domains  = yahoo.com
                message         = X-Forgery: NOT YAHOO SERVER
                condition       = ${if match {$h_Received:}{yahoo.com.via.HTTP}{no}{yes}}
                condition       = ${if match {$h_Received:}{yahoo.com.with.NNFMP}{no}{yes}}