Email Spam Filter – The Essential You Need To Keep Spammers Away From Your Mailbox

Learn how to make an email spam filter indispensable for any email user.

Those days are long gone when the flow of information meant a visit to the nearest post office or the ubiquitous letterbox. With advancements in technology, it transformed into a telephone and then to the email, which is the most preferred mode of official and business communication today. However, email comes with its troubles like spam, which necessitates an email spam filter for anyone using email communication.


spam filtering solutions

What Is A Spam Filter And How Does It Work?

An email spam filter is essentially a software solution whose function is to detect and restrict spam and unsolicited emails coming to an inbox. Once recognized, such unwanted emails are directed to the spam folder instead of the inbox. ESPs usually have an inbuilt spam filtering system by default, which can provide basic functionality. There are also paid spam filter services that have advanced features.

An email spam filter usually detects spam and restricts them based on various parameters such as the content, header, IP address, and sender’s reputation. Spam emails typically have a characteristic nature and patterns that could be discerned from the above parameters. They help the filter to segregate them and keep them away from the inbox. Emails originating from such sources are also marked not to enter the inbox in the future either. Thus a spam filter avoids junk emails and protects the email recipient from threats such as phishing that come with them.


What Do Spam Filters Look For?

A spam filter looks for the usual characteristic features of spam messages exhibited by most such emails. The content of most of these emails is hyperbole and promises of untold success or wealth. Most spam is primarily promotions of products or services, and the spam filter looks for these signs.


The Free Email Spam Filter Industry

Once you decide to get an email spam filter for yourself, you must research the kind you want. There are free, free to try, and paid versions of email spam filters with varying levels of capabilities. Before going ahead with any of them, do read about the limits to which they would function. Most free email spam filters will have limitations. The paid and enterprise versions would offer users a more comprehensive range of options.


Spam Filtering Techniques Used By Email Spam Filters

Many businesses face the arduous task of countering spams and prevent them from overwhelming the email inbox. A spam filter has to be in place to avoid the possibility of a crowded inbox. Here are a few techniques that the spam filters use to create a firewall against the pesky irritants.

Content-wise Spam filtering

This technique will identify specific characteristic terms used in spam emails like ‘bonus,’ ‘discount,’ and ‘claims.’ The filter will mark such emails as spam and stop them from entering the inbox.

Blocking IPs

The filter will identify marked IP addresses, and any email coming from those IPs will be prevented from entering the inbox. It is a more effective way of avoiding spams.


In this technique, a list of email addresses of known spammers is maintained. The spam filter then rejects all emails originating from those addresses. Thus a blacklisted address is always bound to fail from reaching the inbox.


This technique is the opposite of blacklisting. A specific list of addresses of trusted senders is maintained. Only they are allowed to email to the receiver. Any other emails are rejected. It can only be applied in specific accounts or for particular purposes as there is the drawback that all non-approved senders are refused even if some of them are genuine.


Any unfamiliar address is considered spam and rejected in this technique, and a notification sent to the sender. In case it is not spam, the sender sends it again. The email address will be ‘greylisted,’ which means they will be treated as non-spam but not trusted entirely and kept in a separate list. Real spammers won’t bother to read the notification or send the email again.


email spam filter


Choosing The Best Free Spam Filter: A Quick Perspective

As mentioned in the previous segment, the market has a plethora of anti-spam filters. It is pertinent to look for specific functionalities in these filters required from the business point of view. Free, as well as paid, services are available. Most of the paid options have a free trial period. After that, they become subscription-based. They promise 24/7 support and a wide range of functionalities.


Spam Filter Gmail

Gmail has an efficient inbuilt anti-spam mechanism that redirects spam emails into the spam folder. The setting is the default, and the filtering is automatic in a Gmail account, and a user has nothing to do to filter spams. However, if the user thinks any of the emails appearing in the inbox must be regarded as spam and rejected, it can be done manually by the following steps.

1. Click open the email that you think is spam.
2. Click the three vertical dots found on the right top corner of the email to open a dropdown menu.
3. Click ‘Report spam.’ The particular email and any future emails from the address will be sent to the spam folder.

There is an alternative way too.

1. Click the checkbox corresponding to the email on the inbox list to select it. Multiple emails can be chosen this way.
2. From the small icons at the top, click on the one with the exclamation mark. It is the ‘Report spam’ icon.
3. The selected email/s will be sent to the spam folder. The setting applies to future emails from the addresses too.


Spam Filtering Solutions

Different types of spam filtering solutions are available in the market based on the provider type and how they function. Here are the various basic types of spam filtering services.

On-premise Spam Filter

An on-premise spam filter is installed in the internal network of an organization. It is usually integrated into the network firewall.

Cloud-based Spam Filter

A cloud-based spam filter solution can be used as an on-demand service. It is flexible and highly scalable.

Open-source Spam Filter

An open-source spam filtering solution is best for anyone who needs full control to the extent of manipulating the filter design itself.


How To Avoid Spam Filters?

A genuine sender must follow a few simple rules to avoid the email getting marked as spam and discarded.

  • The subject title needs to be less flashy, more business-like, and professional.
  • Avoid words that sound like a flash sale.
  • The format of the email needs to be kept simple and not turned into a collage of colors.
  • In continuation of the point mentioned above, keep ‘creatives’ to the bare minimum.
  • If one has to include URL links, keep it to the bare minimum too.

Email spam filters are an essential part of any organizational framework. Spams are not just a nuisance but are increasingly becoming security threats too. To counter this threat, numerous service providers have solutions that safeguard their clients’ privacy. With the rapid advancements in technology, spammers are becoming smarter too. It has revolutionized the email spam filter market, and better protective suites are being introduced at a fairly regular pace than ever.

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