The board of cloud services business Bulletproof has recommended shareholders vote against the proposed $18 million acquisition by Macquarie Telecom, saying the bid was opportunistic and reflective of the company's historical low in share price.

The statement from the board, excluding chief executive Anthony Woodward who has an interest in the deal, issued on Friday follows on from the business opening up a data room nine days ago to facilitate other companies conducting due diligence ahead of making an offer.