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.
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.
