Dear All, We have postfix-amavisdnew-spamassassin setup on Centos. Since last 2-3 days we are facing this strange issue where by genuine emails sent to users on our mail system are being tagged as UNSOLICIT SPAM and returned to sender. From what I can see, the problem occurs because amavisd-new is looking in the header of the email and due to the difference in the client IP address where the email was generated and the server which actually passed that email to our mail server, it is thinking it is spam. So example, I send an email from my yahoo account to an account on our Mail server. The email header would have something like Recieved: from [my-machine-ip-address] by webxxx.mail.mud.yahoo.com via HTTP Then further up when mail server at yahoo tries to deliver this email to the user on my mail server, our mail server rejects it with the error First upstream SMTP client IP address: [IP_of_yahoo_email_server] webxxx.mail.mud.yahoo.com According to a 'Received:' trace, the message apparently originated at: [my-machine-ip-address], [my-machine-ip-address] If I disable header checks within amavisd-new by changing /etc/amavisd.conf @bypass_header_checks_maps = (1); it works but then it also brings along lots of spam. Can anybody help? Thanks.