On-Premise Secure Email Gateway

Protect against inbound email cyberattacks and prevent outbound data loss with Fortra's Clearswift Email Security gateway appliance.

Block Prevalent Email Attacks with the Clearswift Secure Email Gateway Appliance

The Clearswift on-premise Secure Email Gateway (SEG) protects against spam, viruses, and prevalent threats including phishing, ransomware, and spam by leveraging a Deep Content Inspection Engine. This offers an additional layer of security for content or communications deemed suspicious. 

IT teams need to ensure that information being shared across email both inside and out of the organization is not only secure, but appropriate and compliant. Clearswift’s unparalleled level of inspection and granular policy controls apply the optimal security treatment to your emails in real time reducing the risk of data loss. This keeps your communications safe and flowing, without business disruptions.


Key Features of the Clearswift SEG Appliance

The Clearswift SEG is mail system-agnostic, scalable from SMEs to enterprises and can complement either a cloud-based solution, such as Microsoft 365 and Google Workspace, or on-premise systems like Microsoft Exchange.

Using multiple anti-virus engines, the SEG provides inbound threat protection using traditional signature, heuristic, and cloud assisted lookups to deliver protection against malware, ransomware, and spyware.

Augment the AV engines with Active Code detection and an Active Code removal option or a cloud-based Sandbox from Sophos to detonate the file to ensure no zero-day attacks get through.

Malicious URLs in messages and attachments can be checked using several threat feeds, which can cause the message to be blocked, the URL to be sanitized, or the URL be rewritten so that if the link is clicked the URL will be processed by a Browser Isolation solution.

Data Loss Prevention (DLP) is not just an outbound problem. Depending on your business, you might need to control the content of what’s being received by your employees.

It is imperative that a thorough understanding of the message is performed by the deep content inspection capabilities in order to understand the email body, subject lines, and attachments (such as PDFs, Word documents, and images). This way, they can be scanned for critical information like intellectual property, employee’s personal information, or forgotten content like metadata, revision history, or customer data.

Metadata can include document classification tags from Fortra's Data Classification solutions which can signify whether the content is unclassified, classified, or even top secret.

The understanding of the content and the context is then applied into configured policies to determine if the message should be rejected, held, delivered, delivered encrypted, or sanitized in some way prior to delivery.

The SEG enables compliance with regulations (GDPR, HIPAA, etc.) – detects, protects, and audits emails, and attachments to validate sensitive data. Then it applies the appropriate security remediation according to the specific regulation standards.

Encryption provides security and regulatory compliance needed to keep data secure. Multiple encryption options provide many ways to secure email content by verifying that messages cannot be read by the wrong recipients, and the message stays intact - not modified by anyone from sender to recipient.

The SEG encryption options allow policies to be based on sender, recipient, subject content, message body, attachment types, attachment content, message header or document metadata. Using encryption guarantees confidentiality, integrity, and availability of organizational data.

Clearswift with Cryoserver addresses archiving and compliance in one platform. 

•    Provides C-Level Executives with transparency
•    Adheres to corporate governance and risk management
•    Alleviates IT department storage concerns
•    Offers a forensic archive and compliance system
•    Retains full audited copies of all emails sent to, from, and within a business
•    Preserves data as required by courts and legal practice

Spam and phishing emails are dealt with by a multi-engine, multi-layered spam filtration system, incorporating Signature Engines with machine learning, DMARC, DKIM, SPF, IP Reputation, Greylisting, and URL analysis. This provides a highly accurate and flexible approach where messages can be blocked, held, or delivered with warnings — all based on policy.

Sanitization can take the form of automatic redaction of text with message bodies and attachments including images (such as screen shots) using OCR technology, or document sanitization which can remove hidden metadata, revision information, and autosaved data associated with documents and images.

The Clearswift approach is to remove the information you can see. For example, the credit card number in an email and replace it with ‘zeros’ or asterisks. This functionality also removes information which has been hidden; for example, in a hidden column or row in a spreadsheet which contains PCI data. This method ensures data is not breached, saves time and therefore, saves money.

Product Specifications

Deep Content Inspection Engine

Far greater than any other structural level of verification on the market, Clearswift’s Deep Content Inspection Engine scans content in a multi-stage process:

  • Identifies the file type by file signature
  • Verifies the file structure conformity
  • Extracts content that violates rules in zipped or compressed files, document body, headers, footers, or embedded objects
  • Strips metadata from documents and image files
  • Records what it removed

On-Premise Secure Email Gateway + Microsoft 365


The on-premise Clearswift SEG can be used to provide enhanced Adaptive Data Loss Prevention (A-DLP) protection and complement the M365 hygiene components of the E5 tier with extra coverage, including:

  • More Comprehensive and Easier-to-Configure Adaptive DLP (A-DLP) and Compliance Controls
  • Additional Layer of Ransomware and APT Protection
  • Better Visibility of Policy Violations and Tracking of Message Flow
FunctionalityM365 E5 Tier

             M365 E5 Tier Augmented with                Fortra's Clearswift SEG

Stop & block policy enforcement
Stop & block DLP controls
B2B/B2C encryption
Advanced BEC & brand impersonation protection
Active code detection
Body content analysis
Advanced URL & attachment analysis
Inline sandboxing to protect from malware & APTs 
Active content sanitization to protect from data loss & compliance violations 
Data redaction of sensitive data (e.g., IP, PII, PCI, etc.) 
Automated document sanitization of metadata &version history 
Anti-steganography to sanitize images of hidden data 
Optical Character recognition (OCR) to extend data protection 
Active code removal 


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Why Choose the Clearswift SEG Appliance?

Complete Granular Control
100% Critical Data Visibility
Minimize Business Disruptions

The functionality of the Clearswift Secure Email Gateway and its web-based interface have always been key strong points for us. The solution’s integration with Microsoft 365 was a real bonus. We now have peace of mind that our new cloud email platform has the same level of protection that we'd become accustomed to.

Business Data Operations Dept., County School District, Florida

A Closer Look at the On-Premise Clearswift SEG

A Secure Email Gateway appliance is an on-premise email security solution that monitors emails coming into and out of an organization before they reach an email inbox. As the name suggests, Secure Email Gateway is used as a gateway for emails to protect an organization’s internal email servers from malicious content such as spam, viruses, phishing, and malware.

Working alone or alongside cloud-based email application, the Secure Email Gateway appliance inspects emails for malicious content including spam, viruses, and phishing – a leading email threat. If the SEG determines the email to be safe, based on policies and the latest threat protection, the email is delivered to the intended recipient. If the SEG determines the email contains malicious content, the email can be blocked, quarantined, or sanitized and delivered based on the organization’s policy.

A Secure Email Gateway appliance can provide organizations with anti-virus protection, zero-hour malware detection, sensitive data redaction, and email encryption, all critical features in keeping data safe and companies compliant and protected.

  • Flexible and granular policy control to mitigate risk and ensure compliance  
  • Easy-to-use web-based management interface with role-based access control for
  • Complete data visibility and management of emails entering or leaving your organization
  • Minimal disruption by maintaining consistent collaboration and communication with employees, customers, and partners
  • Comprehensive workflow options that can be tailored to your organization's specific needs

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