https://community.hpe.com/t5/operating-system-hp-ux/sendmail-421-error-server-has-been-blacklisted/m-p/4167427#M320795 Hi all,<BR /><BR />I've just migrated my mail server to another machine ( a virtual machine). All is working fine except for one destination complaining when sending mails. When I do a sendmail -v I get the error:-<BR /><BR />421 mail.noddy.co.uk has refused your connection as your mail server has been temporarily blacklisted.<BR /><BR />Why would I get this error. The IP address is identical and the /etc/mail config aswell?<BR /><BR />Cheers Tue, 25 Mar 2008 13:42:48 GMT Adam Noble 2008-03-25T13:42:48Z https://community.hpe.com/t5/operating-system-hp-ux/sendmail-421-error-server-has-been-blacklisted/m-p/4167427#M320795 Hi all,<BR /><BR />I've just migrated my mail server to another machine ( a virtual machine). All is working fine except for one destination complaining when sending mails. When I do a sendmail -v I get the error:-<BR /><BR />421 mail.noddy.co.uk has refused your connection as your mail server has been temporarily blacklisted.<BR /><BR />Why would I get this error. The IP address is identical and the /etc/mail config aswell?<BR /><BR />Cheers Tue, 25 Mar 2008 13:42:48 GMT https://community.hpe.com/t5/operating-system-hp-ux/sendmail-421-error-server-has-been-blacklisted/m-p/4167427#M320795 Adam Noble 2008-03-25T13:42:48Z https://community.hpe.com/t5/operating-system-hp-ux/sendmail-421-error-server-has-been-blacklisted/m-p/4167428#M320796 Shalom,<BR /><BR />This means the server mail.noddy.co.uk has had sendmail's access file configured to return a reject with error code 421.<BR /><BR />This is commonly done when administrators or automated programs show too much spam has been received from a particular system or IP address.<BR /><BR />SEP Tue, 25 Mar 2008 14:18:06 GMT https://community.hpe.com/t5/operating-system-hp-ux/sendmail-421-error-server-has-been-blacklisted/m-p/4167428#M320796 Steven E. Protter 2008-03-25T14:18:06Z