SORBS is widely considered to be overly aggressive and is probably not a good RBL to trust fully (which is what you're doing if you list it in a reject_rbl_client directive).
You might, at your discretion, want to include SORBS (with a low score) in postscreen_dnsbl_sites (if you are using Postfix's postscreen feature) -- and/or in SpamAssassin (again, assigning it a low score) -- but you've come across an excellent example of why you do *not* want to use SORBS in reject_rbl_client. Different people will have different opinions regarding RBL's, but I am comfortable trusting zen.spamhaus.org and truncate.gbudb.net fully, and I am currently using them in reject_rbl_client checks. Rich Wales ri...@richw.org
