This help section describes the DNS blacklists and the related configuration settings in ORF.
One of the most powerful spam filtering feature of ORF is the ability to check the email source against DNS blacklists. These are independent online databases of known or possible spam sources. During the DNS blacklist check ORF queries these online databases using a DNS query to learn whether the sender is listed as a known spam source.
ORF is shipped with a carefully selected default set of DNS blacklists, but you can also extend or modify the DNS blacklist definitions anytime.
The list of active DNSBLs rarely changes, but if it does (e.g., a DNS Blacklist no longer operates or a new one appears), we release an updated definition set. You can check whether a new definition set is available on our website.
Enable or disable the DNS Blacklist test by clicking the ON / OFF button on top of the page, or on the page.
Set the checkbox of the DNS blacklist that you want to activate or clear the checkbox to de-activate. Only the active blacklists are used for filtering. Before you start using a DNS blacklist, it is strongly recommended to read its description, because one blacklist can include another. Alternatively list sources too aggressive for your taste, may require registration or even may not be free for your use. You can get up-to-date statistics on the DNS blacklists in the Statistics section of our website.
Not sure which blacklists to enable? Check our regularly updated Best Practices Guide if you are interested in our recommendations.
The DNS blacklist on the top of the list is checked first when filtering. Set the check order by selecting the DNS blacklist and moving the DNS blacklist using the Move Up and Move Down buttons. Alternatively, you can set the order by using drag & drop.
Click the New button to add a new DNS blacklist to the list. To modify an existing DNS blacklist, click Modify. DNS blacklist can be deleted using the Delete button or the Delete key.
Right-click on the list and select "Import definitions..." or "Export definitions...". Alternatively, you can perform this from the menu, select or . See more on this below.
See the DNS Blacklist Properties section.
The import and export format for DNS blacklists is XML (see the List Import and Export Formats section).
We publish DNS blacklist usage and efficiency statistics on our website which includes ORF user comments. Visit the statistics page at https://vamsoft.com/r?o-dnsbl-stats. The statistics are generated from the anonymous statistics reports of ORF installations.