Clearswift SECURE Email Gateway: Product overview

Expert Karen Scarfone reviews the Clearswift SECURE Email Gateway product, which monitors incoming and outgoing emails.

Clearswift SECURE Email Gateway is an enterprise email security gateway product used to monitor incoming and outgoing emails for malicious content (e.g., spam, malware, phishing attempts). When the SECURE Email Gateway identifies malicious content in an email, it prevents it from reaching its destination. This stops email-borne attacks from succeeding, thus significantly reducing the damage caused to the enterprise.

Product versions

The Clearswift SECURE Email Gateway can be deployed as a public cloud-based service, a hardware appliance located on premises, on-premises software placed onto a server operating system, or as a virtual appliance running on top of VMware or Microsoft Hyper-V on a traditional server or a private cloud server.

Additional information on Clearswift SECURE Email Gateway deployment options, such as the available models of hardware appliances, is not available.

Security capabilities

Practically all email security gateways offer the same core set of basic security capabilities: antivirus, antimalware, antiphishing and antispam. Clearswift SECURE Email Gateway provides all of these capabilities, and it receives updates every 15 minutes to better detect the latest threats. In addition to the basic capabilities, Clearswift's product also supports data loss prevention (DLP) and email encryption for outbound emails to prevent unauthorized exposure of an organization's sensitive information. However, Clearswift does not provide other advanced capabilities supported by many email security gateways, such as executable sandboxing and the use of threat intelligence feeds.

Detection Accuracy

Clearswift SECURE Email Gateway is designed to detect and block approximately 99.9% of spam messages. Also, the stated false positive rate for Clearswift's product is 1 in 300,000.


A free evaluation of Clearswift SECURE Email Gateway is available on the company's site. Additional information on licensing for the various deployment models was not available.


Clearswift SECURE Email Gateway offers several deployment models, so it should be suitable for organizations of nearly any size. However, because Clearswift does not publish details of the models on its website, such as the specifications for the hardware appliances, any organizations considering Clearswift SECURE Email Gateway should ask Clearswift for additional information in order to more fully evaluate the product. Likewise, licensing information was not available on the Clearswift website; the details of the licensing options and cost could be quite significant in selecting a viable product for deployment.

In terms of security capabilities and detection accuracy, Clearswift's email security gateway has some advantages and disadvantages over competing products. It offers both DLP and email encryption support for outbound emails, which are valuable features not available from all competitors. On the other hand, Clearswift's product does not support executable sandboxing or threat intelligence feed use, both of which are becoming increasingly important for improving the detection of malicious email-borne content. Still, Clearswift's claimed spam detection rate of 99.9% is markedly better than most competing products.

In summary, Clearswift email security gateway provides viable solutions for a wide variety of organizations that do not need sandboxing or threat intelligence feed support in their email security gateways.

Next Steps

In part one of this series, learn the basics of email security gateways in the enterprise

In part two of this series, read about the enterprise use cases for email security gateways

In part three of this series, find out about the purchasing criteria for email security gateway products

In part four of this series, compare the best email security gateways in the industry

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