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Email Gateway: Secure Your Communications

Emails are ubiquitous. In an organization context, this can bring challenges, from establishing the correct distribution and deliverability of emails, internally and externally, to ensuring the security and safety of the content delivered through emails. This is why we have email gateways.

Arsen Team
4 minutes read
What is vishing?

What is an email gateway?

An email gateway is a server or service that acts as an intermediary between an internal email system (such as a corporate email server) and the outside world. It processes and routes incoming and outgoing email messages to ensure they reach their intended destinations. 

Email Gateway key functions

Email gateways have several roles and depending on the one you chose and how you configure it, it can have the following key functions.

Routing and Delivery

First and foremost, the email gateway’s role is to route emails and deliver them to their recipient. Emails won’t go through the same routes if they are internal, external or even are linked to service accounts or groups. 

The email gateway also manages queuing emails during high-traffic periods.

Authentication and authorization

Because the email gateway handles the communication with the outside roles, it has to handle the correct implementation of authentication and authorization protocols such as SPF, DKIM and DMARC.

Filtering and Security

From detecting malwares to filtering spam and content, this is a key security feature of email gateways: they often include email filtering features that help protect email recipients and sometimes filter outgoing emails as well. 

Policy Enforcement

Depending on compliance requirements and established security policies, an email gateway can help at several stages, from applying organizational policies to Data Loss Prevention (DLP) by scanning outgoing content. 

Email archiving and logging

Email gateways are acting as intermediaries and are uniquely places for archives and logging roles. They can store copies of emails for compliance purposes and also log and monitor email traffic for auditing and security purposes.

Encryption

Email Gateways provide encryption as a way to secure communications.

It often uses TLS to encrypt the connection and data in transit and allows a centralized management of encryption policies and protocols for the whole organization. 

Appliances types for email gateway

Like most security appliances, there are cloud and on-premise email gateways.

On-premise gateways can be used for compliance reasons, allowing the organization to keep internal emails on their own servers but it requires higher maintenance and lacks the level of integrations Cloud-based appliances allow through APIs and the cybersecurity ecosystem.

Cloud gateways allow for better scalability, lower maintenance costs and better integrations with third-party APIs, but require organizations to route their emails through the cloud and a subscription fee rather than a one-time investment.

Cloud based email gateways are often preferred. 

Secure Email Gateways Specificities

When it comes to email security, specific email filtering features are used in Secure Email Gateways.

Anti-phishing

Phishing being one of the most prevalent email threats at the moment, a Secure Email Gateway often incorporates anti-phishing protection to identify and block phishing emails.

Sandboxing

Email attachments are often used to spread malware and infect email recipients. Sandboxing features allow to execute and analyze attachment in environments that wouldn’t put the organization at risk.

Content Disarm and Reconstruction (CDR)

These features are often outsourced to third party software but Content Disarm and Reconstruction allows email gateways to remove malware or malicious code from attachments while keeping the attachment content accessible.

For instance, an infected PDF with a malicious piece of code can be modified to remove the malicious code while keeping the text content initially sent. 

Data Loss Prevention (DLP)

Email can be used for voluntary or involuntary data exfiltration. Data Loss Prevention scans emails content to reduce the likelihood of data loss and leaks.

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Frenquently Asked Questions

Organizations use email gateways to enhance email security, filter out spam and malware, enforce compliance with policies and regulations, manage email routing, and ensure the integrity and confidentiality of email communications.

An email gateway intercepts emails as they are sent and received, applying various security measures such as spam filtering, malware detection, content filtering, and encryption. It routes emails to their intended destinations while ensuring compliance with organizational policies.

Key features include spam and malware filtering, content filtering, data loss prevention (DLP), email encryption, email archiving, logging and reporting, and policy enforcement.

An email gateway operates at the server level, processing and securing emails as they pass through the gateway. An email client is an application used by end-users to send, receive, and manage their emails. The gateway applies organization-wide security policies, while the client provides individual user access to email services.

Yes, email gateways often include advanced threat detection capabilities that can identify and block some phishing emails. They use techniques such as URL analysis, sender reputation checks, and machine learning to detect phishing attempts.

Email gateways can enforce encryption policies to ensure that sensitive information is protected during transmission. They use Transport Layer Security (TLS) to secure email communication channels and can also apply content-based encryption to protect the email content itself.

Email gateways enforce compliance by applying policies that align with regulatory requirements. They can perform content filtering to prevent the transmission of sensitive information, archive emails for record-keeping, and provide detailed logs and reports for auditing purposes.

Yes, email gateways can integrate with other security tools such as antivirus software, Data Loss Prevention (DLP) systems, and Security Information and Event Management (SIEM) platforms to provide a comprehensive security solution.

  • Inbound Filtering: Refers to the processing and filtering of incoming emails to protect against threats such as spam, malware, and phishing.
  • Outbound Filtering: Refers to the processing and filtering of outgoing emails to prevent data leaks, ensure compliance, and block the transmission of malicious content from within the organization.

Email gateways use a combination of techniques such as blacklisting, heuristics, machine learning, and signature-based detection to identify and block spam and malware before they reach the recipient’s inbox.

Email gateways are designed to process emails efficiently, but they can introduce slight delays due to filtering and security checks. However, these delays are typically minimal and outweighed by the benefits of enhanced security and compliance.