How to use Spamhaus DNSBL (ZEN and DBL) on our network.
Doing a DNSBL query to Spamhaus ZEN or DBL DNSBL will not reply any data, thus increasing incoming spam on the server.
These DNSBL are used by default in SpamAssassin and are quite good at blocking incoming spam
Install a local recursive DNS server for any outgoing DNS queries.
If you require help with this issue, we suggest contacting our technical support team.
For more information: https://kb.iweb.com/hc/en-us/articles/230242588-Opening-a-Customer-Service-Ticket