Iomart chief executive Angus MacSween said he would continue to expand the company through acquisitions after completing his third takeover in just 12 months.
In April, the Scottish firm bought Liverpool-based domain name and hosting company Switch Media for £1.3m, having snapped up technical hosting specialist Titan Internet for £4.2m in November 2010.
MacSween said: “EQSN has an impressive customer base and is a strong strategic and cultural fit for us.”
EQSN’s clients include the National Health Service (NHS) and several listed companies across the banking, finance and manufacturing sectors.
Its chief executive Alan Lorimer said: “EQSN is a very successful company in its own right. Becoming part of Iomart is a natural next step for us.
“It means that we can offer our customers an extended service portfolio and facilities.”
Lorimer is listed as a shareholder of EQSN, which was launched in 2000, along with fellow directors William Cameron, David Reilly and Brian Walker.
They will receive just under £2.3m in cash up front, with a further £225,000 to follow if the company is successfully integrated into Iomart.
MacSween added: “The purchase of EQSN fits perfectly with our stated intention of looking for acquisitions that add depth and value. We are ambitious to keep growing organically and by acquisitions and will continue to look for similar opportunities.”
MacSween launched Iomart in 1998 and brought in the company’s first revenues the following year through a deal with Sir Richard Branson’s Virgin Group to offer services to businesses.
The company floated on the London Stock Exchange’s Alternative Investment Market (Aim) in 2000 and sold its Ufindus business to BT in 2008 for £20m.
Next week, the company is due to release its results for the six months to 30 September.
Paul Morland, an analyst at house broker Peel Hunt, said the outlook for Iomart was “more silver lining than dark cloud” thanks to its push into cloud computing, through which programs and data are stored remotely on servers and accessed via the internet rather than be kept on desktop or laptop computers.
Morland added: “We have yet to see any sign that economic woes are impacting the desire of companies to move their IT infrastructures into the cloud.
“We understand that EQSN’s customers are slightly larger than in previous deals – adding, in our view, to the quality of this high-growth cloud story.”
Peel Hunt raised its target price on Iomart from 130p to 140p and maintained its “buy” recommendation. Shares closed up 5 per cent at 125.5p.