The Basics of Email Gateway: Understanding How It Works for Enhanced Email Security


Email is the number one method hackers use to infiltrate and compromise company networks, steal or corrupt data and damage reputations. A secure email gateway stops malware, phishing attacks and other unwanted cyberattacks from reaching recipients by putting them into quarantine. Email security solutions typically offer a range of admin controls and reporting. Here are the key components to look for when choosing a secure email gateway:

Spam Filtering

A secure email gateway solution scans both inbound and outbound emails for viruses, malware, and spam. It also blocks email-borne threats like phishing attacks and business email compromise (BEC); thus, this is how email gateway works. Many solutions provide archiving functionality for compliance and data management purposes. Email is one of the most common attack vectors for cyber attackers, as it allows them to infiltrate a company’s systems and corrupt or steal its data.

Attackers target companies by sending phishing emails to employees with malicious attachments or links. If an employee clicks a malicious link or downloads an infected attachment, their computer is infected with malware and could spread the infection to other computers within the network. SEGs prevent insidious threats by using various methods for filtering out unwanted and virus-carrying emails, such as list-based filters, word-based filters, and heuristic and Bayesian filters. These filters work by analyzing the content of the message and its metadata for suspicious patterns. To identify potential threats, they may also check the email subject line, header, photos, fonts, colors, and attachments.

Organizations can deploy their SEG on premises with a physical or virtual appliance or in the cloud. The choice depends on the company’s comfort level with migrating services to the cloud and its privacy and security standards for data outside of the enterprise network boundary.

Post Delivery Protection

Email is a prime attack vector for cyber attackers because it’s relatively easy to get through to employees and access sensitive information. An attacker can send an email with malicious links or attachments that can infect a user’s device and lead to data leaks, which may have devastating consequences for a company. An Email Gateway aims to protect a network from the threat of malicious emails and their attachments. This can be done by detecting and blocking spam, phishing, ransomware, malware, and other email-borne threats. It can also be accomplished by encrypting outbound messages and scanning them for sensitive content.

An Email Security Gateway can be deployed on-premise, as an appliance, or in the cloud. The choice will often be based on the organization’s comfort level with having services and data exist outside the firewall of its IT infrastructure. A secure email gateway can block malware and viruses by analyzing all incoming and outgoing emails. It can identify phishing attacks by checking the authenticity of sender addresses and implementing anti-fraud technologies, like sender policy framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting and Conformance (DMARC). Email gateway solutions also often include an email archiving functionality to store emails for compliance and business continuity. This helps to ensure that important data is not lost, even if an employee’s email client becomes unavailable for some reason.


In a world where malware, phishing attacks and ransomware are still prevalent and often the cause of data breaches, email security gateways prevent threats from reaching endpoint devices and compromising employee credentials, email systems and sensitive company information. They are essential to an organization’s cybersecurity protection plan. As the name suggests, a secure email gateway (SEG) works like an email firewall, redirecting incoming and outgoing emails to inspect and analyze them for malicious content.

Once the SEG determines that a message isn’t safe, it either blocks the email or quarantines it. Depending on the type of threat, it may also flag the message and send a warning to the solution or network administrator. Sandboxing is a key component of a solid email security gateway that uses a combination of artificial intelligence, machine learning, signature matching and behavioral analysis to identify threats hidden in attachments and URLs. Once the scanning application identifies a potentially dangerous extension, it diverts the email to a “sandbox” environment where it is virtually executed to examine the side effects on the operating system and determine whether or not it is malicious.

While sandboxing can help, it is important to remember that cybercriminals‘ methods constantly evolve. The goal is to bypass or trick the security system and evade detection. This is why a well-rounded email security gateway that combines multiple layers of protection, such as sandboxing and dynamic file analysis, is critical to an organization’s success.

Malware Scanning

Email is one of the most widely used methods for business communication, but it’s also the simplest tool for hackers to gain entry into systems and destroy or corrupt data. With an estimated 4.03 billion email users worldwide, cyberattacks like phishing, ransomware, Business Email Compromise (BEC), trojans, and malware are increasingly dangerous for organizations and individuals.

A secure gateway scans emails for threats to prevent these attacks by checking several aspects. This analysis is performed during the inbound and outbound email processing and can include content filtering, sandboxing, content defense technologies, and advanced machine learning algorithms. If the email is considered safe, it will be delivered to an internal server or service to a user’s inbox.

If a threat is detected, the gateway will block or quarantine it for further investigation by the solution administrator. Email gateways can be deployed on-premise or in the cloud, depending on an organization’s cybersecurity needs. With a robust email security solution, businesses can reduce the risk of data breaches and other repercussions, such as non-compliance fines and reputation damage.