Clearswift

Clearswift was founded as NET-TEL in 1982.^[2][3] One of the co-founders, John Horton, had previously worked at GEC and Acorn Computers.^[4]

In 1988, NET-TEL launched Route400, the world's first mail client for MS-DOS (using the X.400 protocol). It was later ported to other platforms.^[5][6]

In 1998, NET-TEL switched its main business to content filtering, as the popularity of the Microsoft Exchange Client took away the mail client market.^[6]

In 2001, NET-TEL was rebranded as Clearswift, after a round of venture capital fundraising.^[7]

In 2002, Clearswift acquired Content Technologies from Baltimore Technologies, along with the MIMEsweeper brand.^[8]

Clearswift extended the MIMEsweeper line to include web and instant messaging filtering. These were marketed as protecting against the leakage of confidential company information on social networking sites - Clearswift argues that instead of banning Web 2.0 sites and services entirely, businesses can actually gain a competitive advantage by making use of them, provided their use is monitored.^[9][10]

In 2003, the company received $6.07 million from its shareholders, including venture capital funds managed by Amadeus Capital Partners, BA Capital Partners, Cazenove Private Equity, and Kennet Partners.^[11] Also, it was reported that Clearswift were the providers of a new email filtering system at the House of Commons, responsible for blocking Welsh language emails as "inappropriate content", and preventing MPs receiving copies of a Sexual Offences Bill.^[12] Clearswift would not confirm that the House of Commons was a customer, citing customer confidentiality reasons.^[7]

In April 2005 Clearswift began to market an SMTP appliance (email gateway) based upon the technology.^[13]

In January 2008, failure to renew a domain name caused loss of email services to 5% of Clearswift's customers.^[14]

In Dec 2009, Clearswift sold the Deep-Secure, Bastion and Flashpoint products in to a spin-off company, "Deep Secure".^{[citation needed]}

In November 2011, Clearswift was sold to Lyceum Capital.^[15]

In August 2012, Clearswift acquired Jedda Systems Pty Ltd.^[16]

In February 2013, Clearswift acquired Microdasys in order to strengthen its web product line.^[17]

In January 2017, Clearswift was acquired by Swiss defense company RUAG as part of its RUAG Defence Cyber division.^[18]

In December 2019, Clearswift was acquired by HelpSystems to expand its cybersecurity portfolio.^[19]

Clearswift has its main engineering office based in Arlington Business Park^[20] (Theale, UK). A smaller engineering office is in Adelaide, Australia which was part of the Jedda acquisition.^[21]