The primary function of a spam filter is to separate good email from bad ones and place it in the mailbox. When email filtering is enabled, it means that you allow the software to analyze the emails and dissect phishing content from the legitimate, and move them to the junk/spam folder.

A spam filter has emerged as an increasingly crucial part of the email delivery process. Therefore, they have become more robust and sophisticated over time. Spam filters do not let your emails land in the inbox if they suspect anything spammy.

Spam emails have been a problem for a long time, and when this concept was invented, the world found it a brand new way to communicate. Not only this, the attackers found this an easy way to find the victims.

Spammers send out hundreds of thousands of emails, many of them caught by the spam filters pretending to be a sight for the sore eyes of the recipients. Too much data is available on the web speaking volumes about spam filters and their functionality.

Unfortunately, everything is not accurate. Email filtering has been around for a while, and it plays a major role in the cybersecurity plan.

In this article, we shall discuss what is an email filter, and how it works, keep reading.

Table of Contents

  1. What is a spam filter?
  2. How do spam filters work?
  3. Types of spam filters
    • Email service provider spam filter
    • Desktop spam filters
    • Third-party spam filters
  4. How does a spam filter help you?

What Is a Spam Filter?

Spam filters follow algorithms that don’t let any infected email land in the mailbox. Various spam-detecting filters are there with different spam detection capacities ranging from simple pattern matching to machine learning.

What is a spam filter | Mumara

Spam filters work a lot to discriminate between solicited and unsolicited messages, and detect emails that contain viruses. There is no single spam-detecting filter available that is used by all the email service providers, fairly, every mailbox service provider uses different algorithms and machine learning as spam filters.

The primary function of a spam filter is to separate good email from bad ones and place it in the mailbox. When email filtering is enabled, it means that you allow the software to analyze the emails and dissect phishing content from the legitimate, and move them to the junk/spam folder.

Spam filters serve greatly to the business because they don’t allow suspicious content to land in the employees’ folders in order to save it from any kind of malware.

How Do Spam Filters Work?

As we have discussed in the above lines that email spam filters do not let phishing emails to be landed in the inbox. Now the question arises what are the criteria these filters follow to shift the illegitimate messages to the junk folder?

The common mechanism they follow is spammy words, such as “earn money”, “free”, etc. Also, if a sender sends an email to the email address instead of a contact, it will trigger the spam filter.

That is the reason when you send a newsletter to the person who hasn’t subscribed to receive one from your, your newsletter will be ended in the junk folder. Not only the specific words, and subscribing/unsubscribing for newsletter criteria, there is something more than that.

Sender reputation is another important factor in this regard. If the sender’s IP is previously used for spamming, there is nothing to be surprised about that your text messages will be landing in the spam folder.

Spam filters will recognize these IPs with a bad reputation instantaneously, and will be flagged again to be destined to the junk folder. Further, email copy and design in one of the most important elements that decide the email placement.

The only text and only emails are meant to be placed in the spam folder. Spam filters are so genius that they remember the senders who have been involved in sending links containing some malware. Also, users need to engage with your emails, if not, the filters will halt them from going to the inbox.

Types of Spam Filters

There are three main types of spam filters:

  1. Email service provider (ESP) spam filters
  2. Desktop spam filters
  3. Third-party spam filters

Let us read about them one by one.

Email Service Provider Spam Filters

Email service provider spam filters are used by email users without knowing. ESPs such as Gmail, Yahoo, Hotmail, etc. provide cloud-based services where email users organize, send, and receive their emails.

ESP filter | Mumara

These email service providers come up with built-in spam filters that use advanced-level algorithms that apply machine learning to show you the messages you need. Other messages are shifted to the junk folder automatically.

Desktop Spam Filters

These filters are basically the software that is purchased and installed on the computers. These filters create an extra layer of protection for that malware that somehow manages to take place in the mailbox, and gets opened.

You can configure the level of protection as per your requirements and the spam tolerance. Over time, email spam filters are getting more and more intelligent, and desktop filters are losing popularity.

Third-Party Spam Filters

The functionality of third-party spam filters is just like desktop spam filters. They work to provide an extra and fine layer for spam detection. Desktop spam filters are installed on the computers, whereas, third-party spam filters are added to the email systems.

Where they detect any malware if unchecked by the ESP filters. Companies deploy these filters to avoid phishing attacks and take benefit from robust analytics to evaluate accurate spam activity.

How Does a Spam Filter Help You?

We have learned that spam-detecting filters are responsible to shift junk emails to the spam folder. Further, this task is not as easy as it seems. The reason behind this is that spammers always try to find modern ways of attack.

spam filter | Mumara

If email service providers do not update the filters, the spammers find a way to land in the inbox. Therefore, the upgradation is an ever-changing process. For example, spam filters detect spam words, and those words are known to anyone.

Spammers mold the language of the email body, subject line, preheader, etc., and get a safe passage to the inbox of the recipients. Updated spam-detecting filters provide a security layer, and protect organizations from being attacked by malware.

Harmful emails are stopped by the filters and companies get saved from fraudulent attacks well before time. 

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Eric Lee

A reader, writer, researcher, and explorer!

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