Answer
To configure IP DNS Blocklist, follow the steps below.
- Open the GFI MailEssentials Configuration console
- Expand Anti-Spam and then Anti-Spam Filters
- Select IP DNS Blocklist
- Inside the empty text box under IP DNS, enter the following desired DNSBL List's Address
- Select Add IP DNS Blocklist
- Ensure that the DNS blocklist is still valid and can perform successful reverse look ups