Anti Spam 101: What is a Spam Filter?

So what is a spam filter and how do they work? Considering that around 270 billion emails and messages speed through the Internet daily and a whopping 50% of this number is spam, you can imagine the kind of tsunami systems are fending off day in and day out. In this context, anti spam measures save system resources by actively blocking spam even before they enter. Let's find out how anti spam work to further appreciate what they do for email accounts on a daily basis.

What is a Spam Filter? How Anti Spam Block Unsolicited Messages

Anti spam or spam filters work primarily through several protocols or rules on what to block. This is because spam flood in through different methods and anti spam protocols confront each flood through these particular rules. Each anti spam measure works through these specific filters:

Types of Spam Filters

  1. Blacklist filters
  2. Header filters
  3. Rules-based filters
  4. Challenge-response filters
  5. Content filters
  6.  Permission filters

  • 1. Blacklist filters – Anti spam professionals collect the server addresses of known spammers and creates rules for servers to monitor and label messages coming from these servers. Some ISPs which do not have strong anti spam measures or tolerate spammers within their system tend to have messages from their accounts tagged as spam.
  • 2. Header filters – These anti spam filters work on checking if there is anything remiss on the header information of the message. Each email has its own unique message identifier – spam use only one identifier for a batch of messages. Anti spam filters catch the duplication or see where the message is coming from through the headers and block the message accordingly.
  • 3. Rules-based filters – These anti spam filters tag messages as spam based on specific programmed criteria. For example, if a message has a phrase like "Nigerian Prince" or "viagra," chances are the message will land in the Spam Folder.
  • 4. Challenge-response filters – These anti spam filters work by asking people who want to send a message to enter a code before being able to send you a message.
  • 5. Content filters – These anti spam filters check messages for specific phrases or content which will indicate if it is spam or not.
  • 6. Permission filters – This particular anti spam filter works by asking permission from the receiver if they are willing to accept a message from a particular sender. This in effect, whitelists the email address of the sender if the receiver grants permission.

What is a Spam Filter? How Spam Filters are Installed

These anti spam measures are installed in three ways. Some anti spam filters exist primarily as cloud applications like Comodo Antispam for example. There are anti spam filters which come in the form of hardware. Professional IT techs install these equipment in the premises of the company. Some companies buy licenses for anti spam software and install them along with their email clients like Outlook.

What is a Spam Filter? Here's an Example of an Anti Spam Solution That Works

Comodo Antispam's email protection is robust and better than other solutions in the market right now. This email protection is largely due to three layers of proprietary Comodo technology. There's the advanced email protection algorithm, email protection containment technology, and the command console. Here's what Comodo Antispam provides in terms of advantages in line with the ones other cloud services providers offer in terms of email protection:

  • 1. A centralized command console which puts user and group mail management under the fingertips of MSP personnel.

Admins can profile their clients' users and give each user a different security profile. Done this way, companies can better their anti spam protection by applying security features and restrictions on a case per case basis. Administrators will be able to shield the most vulnerable users' email security by doing so.

  • 2. Comodo's unique containment technology works to cage zero-day threats entering cloud services.