Add DNSBLs to deny incoming spam messages

[d19dotca]

I'd like to request that administrators be given the option to add extra DNSBLs (if they desire) to the "zone" which will deny connections to the mail server from further processing by known spamming IPs.

Instructions to do this manually (but won't survive service restarts) was written in the related discussion post.

[robi]

Yes, this needs to be a setting! Even if manual via console.