Peter N. M. Hansteen<p>I was reminded that the old "Effective Spam and Malware Countermeasures - Network Noise Reduction Using Free Tools" <a href="https://nxdomain.no/~peter/effective_spam_and_malware_countermeasures.html" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">nxdomain.no/~peter/effective_s</span><span class="invisible">pam_and_malware_countermeasures.html</span></a> (a somewhat overweight article/blogpost) might still be worth your time if you are that kind of person <a href="https://mastodon.social/tags/openbsd" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>openbsd</span></a> <a href="https://mastodon.social/tags/spamd" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>spamd</span></a> <a href="https://mastodon.social/tags/antispam" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>antispam</span></a> <a href="https://mastodon.social/tags/greylisting" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>greylisting</span></a> <a href="https://mastodon.social/tags/greytrapping" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>greytrapping</span></a> <a href="https://mastodon.social/tags/cybercrime" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>cybercrime</span></a> <a href="https://mastodon.social/tags/freebsd" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>freebsd</span></a> <a href="https://mastodon.social/tags/freesoftware" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>freesoftware</span></a> <a href="https://mastodon.social/tags/libresoftware" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>libresoftware</span></a> (if nothing else for the references to other items of interest)</p>