I am getting this error: ----- Transcript of session follows ----- ... while talking to mail-in.cbl.abuseat.org.: >>> DATA <<< 550 HELO for IP 24.123.23.170 was "unifiedpaging.messagenetsystems.com" 550 5.1.1 <helocheck at cbl.abuseat.org>... User unknown <<< 503-All RCPT commands were rejected with this error: <<< 503-HELO for IP 24.123.23.170 was "unifiedpaging.messagenetsystems.com" <<< 503 Valid RCPT command must precede DATA when checking my outgoing mail from http://cbl.abuseat.org/helocheck.html What am I supposed to change on my centos 5 system to no longer be on the CBL listing. I have manually remove the entry but something needs to change so it doesnt get back the list again. The FAQ's talk about windows not linux. What do I do to change sendmail? Jerry