MailMum Block

Howto block mailservers using uncommon TLDs in hostname through Postfix

Blocking or blacklisting entire Top Level Domains (TLDs) used for hostname in email server setup can be a very effective solution to stop low reputation mail servers delivering mails to your email system(s). As most email providers use common TLDs like .net, .com or .de in their email setup, you can selectively block new or low reputation TLDs and this way reducing a lot of unwanted emails. If you are looking for a tutorial to blocking/blacklisting sender (users/clients) using specific TLD, this tutorial is the right one for you: Howto Block Entire TLDs in Postfix for Senders.

Howto Block Entire TLDs in Postfix

Blocking or blacklisting entire Top Level Domains (TLDs) in Postfix mail server may have a big impact to reduce spam, phishing, and other unwanted emails. Dependent on the use case of your systems it is a valid and effective solution. The only drawback is, to monitor your email traffic and check, whether valid emails from blocked TLDs are sent to your systems. Blocking a whole TLD is mostly a temporary thing, as the bad guys move on if the domains on a specific TLD are not usable for their cases.