sendmail 421 error server has been blacklisted

[Adam Noble]

Hi all,

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:-

421 mail.noddy.co.uk has refused your connection as your mail server has been temporarily blacklisted.

Why would I get this error. The IP address is identical and the /etc/mail config aswell?

Cheers

[Steven E. Protter · Accepted solution]

Shalom,

This means the server mail.noddy.co.uk has had sendmail's access file configured to return a reject with error code 421.

This is commonly done when administrators or automated programs show too much spam has been received from a particular system or IP address.

SEP