What Are Spam Filters and How Do They Work?

email spam protection
Reading Time: 7 minutes

Spam filters are applications that protect your data by identifying and blocking spam emails before they reach your inbox. They help ensure that you only receive the emails that matter – keeping your personal information safe and improving your productivity by reducing the number of spam emails in your inbox.

Without such protections, spam emails, often referred to as junk mail, can over-run your inbox. These emails are not only annoying, they can also carry malware and pose significant security risks.

Fortunately, there is a solution – PMG Proxmox Mail Gateway by Velocity Host “is a comprehensive open-source email security platform helping protect your inbox from email threats,”

What Does Spam Email Mean?

Spam emails are unsolicited and often irrelevant messages sent to a large number of recipients. These emails typically aim to promote products, services, or fraudulent schemes.

Types of spam emails include:

  • Marketing Messages – These emails promote products or services and are often sent in bulk. While some might be legitimate, many are unwanted and irrelevant.
  • Scams – These emails attempt to deceive recipients into providing personal or financial information. Common examples include phishing emails that mimic legitimate organisations to steal sensitive data like passwords and credit card numbers.
  • Malware-Laden Emails – These contain malicious attachments or links designed to infect the recipient’s computer with viruses, spyware, or other harmful software.

Velocity Host’s Proxmox solution is able to detect spam and block it, protecting you from security threats and keeping your inbox more manageable.

Is Spam Filtering Necessary?

Spam filtering is necessary for several reasons – it protects against cyber threats, ensures legal compliance, and enhances productivity.

Staying Safe Online

Spam emails are not just annoying; they can also be dangerous. They often carry malware, phishing links, and other cyber threats that can steal your personal information or infect your devices with malicious software.

Velocity Host reduces the potential ofmalware by blocking emails that contain harmful attachments or links. At the same time, PMG aids in identifying  and filtering phishing emails that attempt to trick you into providing sensitive information such as passwords or credit card details. PMG also reduces the risk of cyber attacks that would otherwise compromise email security.

Productivity and Efficiency

The average person spends around two hours a day checking and responding to emails. Staying on top of your inbox not only helps you stay productive, it also helps to keep your mind clear so that you can focus on your most important tasks. Let’s face it – you probably have enough to deal with without being distracted by emails that belong in spam folders.

Legal Compliance

Spam filters help reduce and in some cases prevent phishing attacks, which can be used to steal sensitive information or financial data. By blocking these emails, spam filters reduce the risk of compliance breaches related to data security and financial regulations.

Saves Money

Spam filters may even save you money. Manually managing spam is time-consuming and can requires dedicated staff depending on the size of your organisation. When you automate the process, businesses can reduce the costs associated with manual spam management. Additionally, by preventing cyber threats, spam filters help avoid the financial repercussions of security breaches.

How Is an Email Classified as Spam?

Email spam filters work in a variety of ways to determine whether an email is spam including analysing the content, structure, and sender.

Content Analysis

One of the key indicators of spam emails is the content. Effective spam filters will look for things such as:

  • Keywords and Phrases – Words commonly used in spam emails, like “free,” “win,” or “urgent.”
  • Links and Attachments – Presence of suspicious URLs or attachments that might lead to malicious sites or contain malware.
  • Formatting – Use of excessive capital letters, exclamation points, and other visual elements often found in spam emails.

Sender Reputation

The sender’s reputation can also indicate a spam email. Spam filters such as Velocity Host’s ProxMox maintain lists of IP addresses that have a history of sending spam. This means that emails from known spammers and blacklisted IP addresses are automatically sent to your spam inbox or blocked.

The sender domain is also evaluated for it’s history and behaviour, if the domain has been associated with spam in the past, the email will be scrutinised.

Header Information

Abnormalities in headers can also indicate a spam email, for example, if the sender and the address don’t match.

Proxmox Mail Gateway uses key protocols such as:

  • DKIM (DomainKeys Identified Mail) – DKIM ensures the email content hasn’t been tampered with by adding a digital signature.
  • SPF (Sender Policy Framework) – SPF verifies that the email is sent from an authorized server listed in the sender’s domain DNS (Domain Name System) records.
  • DMARC (Domain-based Message Authentication, Reporting, and Conformance) – DMARC builds on these by setting policies for handling emails that fail DKIM or SPF checks, enhancing overall email security.

Bayesian Filter

A Bayesian filter is a type of spam filter that uses statistical methods to determine the likelihood that an email is spam. It works by comparing the content of emails with a database of known spam and legitimate emails. Here’s how it functions:

  • Statistical Analysis – The filter analyzes the frequency of words and phrases in the email content, assigning probabilities based on past occurrences in spam and non-spam emails.
  • Spam Score Calculation – Using Bayesian probability, it calculates a “spam score” for the email. The email is classified as spam if the score exceeds a certain threshold.
  • Learning Over Time – The filter improves its accuracy over time. When you mark an email as spam or not spam, the filter adjusts its calculations to identify similar emails in the future better.

Behavioural Analysis and Machine Learning

Proxmox Mail Gateway will track how you interact with emails using rule training methods that help identify false positives – high engagement suggests that specific senders are legitimate while low engagement or high deletion rates can trigger spam filters.

Proxmox Mail Gateway leverages 3rd party advanced machine-learning algorithmsto stay ahead of evolving spam techniques. By analyzing vast datasets of emails, the systems continuously learns and adapts to new spam patterns, ensuring robust and up-to-date spam protection. This proactive approach keeps our email security measures highly effective and resilient against emerging threats.

Why Velocity Host has the Best Spam Filter

Velocity Host has been supporting businesses of all sizes for over a decade. Our commitment to providing simple solutions to complex problems, and outstanding customer support has been the key to our success.

PMG – Proxmox Mail Gateway by Velocity Host

  • Comprehensive Solutions – Advanced spam filtering solutions designed to protect your inbox from unwanted emails. All emails are thoroughly scanned and filtered before they make their way to your inbox, creating a strong barrier against spam, phishing, and malware.
  • Seamless Integration – Our filtering solutions are easy to integrate with your existing email systems. This makes the transition simple and non-disruptive to your business.
  • User-Friendly Interface – We understand that not everyone is a tech-wiz, which is why we prioritise user-friendliness. Manage your email settings effortlessly to keep your inbox clutter-free and secure.
  • Enhanced Security and Performance – We use advanced algorithms that include 3rd party machine learning techniques, Real Time Block Lists and advanced user trained rules to continuously learn and adapt to new spam tactics. This proactive approach ensures that even the latest spam threats are identified 95% of the time and blocked.
  • Australian-Based Support – Velocity Host is Australian-based which ensures that you have access to reliable assistance whenever you need it. We operate out of Australia’s 1st commercial Tier 4 data centre, guaranteeing the highest level of security and performance.
  • Cost-Effective and Scalable – We pride ourselves on our affordability and scalability allowing us to cater to businesses of all sizes. Regardless of whether you are a small business or a large corporation, Velocity Host offers flexible plans that can grow with your needs. This scalability ensures that you only pay for what you need.

What Role do Internet Service Providers (ISPs) Play in Spam Protection?

ISP’s provide their own basic spam filters when subscribed to a mail service, d elivering a crucial first line of defence. However, they are insufficient on their own for several reasons:

  • Enhanced Features – Advanced spam filters  includes features such as phishing protection, attachment scanning, and real-time updates, which are not fully covered by basic ISP filters.
  • Additional Layers of Protection – Proxmox Mail Gateway offers additional security features, such as advanced machine learning algorithms, Bayesian filtering, and content-specific rules, which provide a higher level of spam detection.
  • User Control – Proxmox Mail Gateway allows for more user control, enabling users to fine-tune settings, create custom rules, and manage whitelists and blacklists more effectively.
  • False Positives and Negatives – ISP filters can misclassify emails, either letting spam through (false negatives) or marking legitimate emails as spam (false positives) without allowing the user to fine tune the behaviour. Having an additional spam filter helps minimise these errors by providing an extra layer of scrutiny.

What Are Spam Filters and How Do They Work? FAQ

What are spam filters?

Spam filters are applications  that are used to detect and block unwanted emails known as spam. They analyse emails before they reach your inbox to reduce and prevent spam from reaching your inbox.

What are the benefits of spam filters?

Effective spam filters enhance security, improve productivity and reduce costs – ensuring that your email communications remain safe and efficient.

What are the different types of spam filters?

There are several types of spam filters, including:

  • Content Filters – Analyse the text of emails for common spam indicators.
  • Blacklist Filters – Block emails from known spam senders.
  • Header Filters – Examine the email header for suspicious information.
  • Rule-Based Filters – Use predefined rules to identify spam.
  • Bayesian Filters – Use statistical methods to determine the probability of an email being spam.
  • Challenge-Response Filters – Require unknown senders to verify their identity before the email is delivered.

How does a spam folder automatically manage spam emails?

When Proxmox Mail Gateway detects a spam email, it will automatically mark the email with a ##SPAM tag moving it into the spam / junk folder – keeping your inbox free from clutter and potential threats.

A daily report is sent listing the emails that have been caught and allowing you to ‘whitelist, blacklist, deliver or delete’ the emails to help constantly train the SPAM system to improve the filtering.

What are desktop spam filters?

Desktop spam filters are installed on individual computers normally as part of an endpoint all in 1 antivirus/ malware solution. These  applications try to filter the spam once they have already arrived to your email client making them less effective using external filters in conjunction with desktop antivirus will deliver a better overall solution.

Why do spammers tend to change their tactics frequently?

Spammers continually change their tactics to avoid spam filters. This is why it is so important to have an effective spam filter that is continuously improving and staying ahead of new tactics.

Can spam filters sometimes block legitimate emails?

Yes, spam filters sometimes block legitimate emails, known as false positives. If you are expecting an email you haven’t received it is worth checking your spam inbox and checking PMG if the email has been blocked. If you mark a legitimate email as not spam, Proxmox Mail Gateway will learn and improve its accuracy.

How can users avoid spam filters when sending legitimate emails?

To avoid spam filters, users should:

  • Use a reputable email service provider.
  • Avoid using spam-like language or excessive links.
  • Ensure their emails have clear and legitimate content.
  • Maintain a good sender reputation.
  • Only send bulk emails via an approved bulk sending service like MailChimp or other dedicated 3rd party bulk sender.

Enhancing Email Security with Velocity Host

Spam filters are vital for businesses of all sizes in Australia. They protect your inbox from malware, phishing, and other cyber threats, keeping personal and business information secure. Effective spam filters also boost productivity by reducing inbox clutter and help organisations stay compliant with anti-spam laws.

With Velocity Host, you can relax knowing your inbox is safer, allowing you to focus on what truly matters. Our seamless integration into existing email systems ensures an easy transition without disrupting your business.

Got questions? Do not hesitate to contact us, a member of our friendly team will be happy to assist you. Let’s secure your email and streamline your communication today.


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