[SLUG] Rejecting SPAM with SURBL

[Nigel Allen <dna@xxxxxxxxxxx>]

Greetings

Suffering (like who isn't) with the constant deluge of spam for both our 
domains and others that we act as secondary MX for, we decided to 
tighten our groip a little.

Currently running FC7 with sendmail, spamassassin and mimedefang.

We have got it to the stage where suspected email is having {Spam?} 
inserted into the subject but we now want to go one stage further and 
reject anything that appears on multi.surbl.org.

We have got the SURBL lookup working - we are seeing things like this in 
the maillog:

> May  7 13:39:54 sydsrv01 sendmail[1904]: m473dbGb001904: Milter change 
> (add): header: X-Spam-Score: 17.298 (*****************) 
> BAYES_99,EXTRA_MPART_TYPE,HTML_IMAGE_ONLY_16,HTML_MESSAGE,HTML_SHORT_LINK_IMG_2,PART_CID_STOCK,PART_CID_STOCK_LESS,RCVD_IN_PBL,STOCK_IMG_HDR_FROM,STOCK_IMG_HTML,T_TVD_FW_GRAPHIC_ID1,URIBL_AB_SURBL,URIBL_BLACK,URIBL_JP_SURBL,URIBL_SC_SURBL
but the email is still being forwarded to the recipient. Unfortunately 
some of the recipients (like BigPond) have surbl working properly and 
are now rejecting our forwarded messages - which bounce back etc etc etc.

Question: How can I set up the above combination so that any email that 
is positive from SURBL is simply rejected during the delivery phase?

Gently please, with Crayola. Definitely not a sendmail guru here.

Thanks and Regards

Nigel.