Symantec Corp. said Wednesday said it will acquire anti-spam firm Brightmail Inc. for $370 million in an all-cash transaction.

Brightmail has roughly 1,800 business customers, including Avaya, Deutsche Bank, Eastman, Microsoft, and Terra Lycos. It also provides anti-spam technology to large Internet service providers such as AT&T WorldNet, EarthLink, and Verizon Online.

The acquisition must meet typical regulatory approval and is expected to close in July.

Brightmail's technology will complement Symantec's antivirus offerings and strengthen its ability to provide anti-spam technology to customers at their Internet gateways, security analysts say. "Spam is clearly a tactical problem for companies, and this acquisition will help Symantec broaden its offerings," says Pete Lindstrom, research director at Spire Security.

The move continues a consolidation trend evident in Tumbleweed Communications' acquisition of Corvigo in March and in last year's purchases of ActiveState, Elron Software, and Deersoft by Sophos, Zix, and Network Associates, respectively.