This is the answer, more detail: https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-mfa-howitworks. Source: about 2 years ago

Make sure that you back-up the active app-configuration, this way you have an easier way to recover; make sure you are allowed to verify using more than an authenticator, more here. Source: about 3 years ago

Spamassassin or rspamd or ASSP. All very good. Spamassassin just works, but you need to feed it a good cohort of spam and ham (about 1000 messages each). Most people only send it the spam which will then bias it quite a bit and not have it classify spam as spam unless it's the worst of the bunch. Spamassassin is a filter for your mail server. Rspamd is the same idea. ASSP is highly configurable and a proxy. Source: about 1 year ago

I'm currently looking into using a Bayesian spam filter like Bogofilter or Apache Spamassassin to help out. I'd run the contents of my Contact Us form through the filter after the initial validation, and if the contents are below my spam threshold, I would actually send out the contact us request. Source: almost 3 years ago

The famous spam filter SpamAssassin. Score: -0.6. A score below -5 is considered spam. -0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid This rule is automatically applied if your email contains a DKIM signature but other positive rules will also be added if your DKIM signature is valid. See immediately below. 0.1 DKIM_VALID Message has at least one valid DKIM or DK... Source: almost 3 years ago

To detect whether incoming emails are malicious, mail servers also use spam scanners, such as Apache's popular SpamAssasin. The internal workings of these spam scanners can be somewhat complicated (involving Naive Bayes Classifiers on trained, large datasets, for the curious), but the primary takeaway is that these classification systems typically assign a numerical point value to an incoming email to determine... - Source: dev.to / about 3 years ago