I have notice of this problem to use zen.spamhaus.org RBL: After some investigation I have discovered that this error is due to a new policy from spamhaus.org: (Spamhaus Data Query Service) I'm already using a local DNS and what I should to do is a new way to config postfix RBL check Here is information on how to correctly configure commonly used MTAs for use with the public mirrors, But put "zen.spamhaus.org=127.0.0.[2..11]" into ispconfig is not possible. For now I have remove zen.spamhaus from my RBL list. What is the best way to configure these RBL config? Many thanks Dario
I guess the best way will be to add support for that in ISPConfig. I'll add a feature request for that.
For now I have resolve to remove forwarder to Public DNS into my recursive local bind DNS and replace zen.spamhaus.org into ispconfig. All work fine. Useful link: https://serverfault.com/questions/1190478/spamhaus-open-resolver-error-with-own-recursive-dns