Cisco to buy maker of spam filters

NEW YORK —  Network equipment maker Cisco Systems Inc. said Thursday that it would buy e-mail and Web security firm IronPort Systems Inc. for $830 million to tap growing demand for antivirus and anti-spam software.

The acquisition of the privately held software and equipment vendor is Cisco’s latest move to grow by integrating niche technologies that complement its main product line of routers and switches, which direct Internet traffic.

Cisco said the acquisition, its fifth-largest, would enable it to offer corporate clients a more comprehensive range of products.

Shares of the San Jose-based company rose 73 cents to $28.46 on Thursday.

San Bruno, Calif.-based IronPort is known for “reputation filters” that block spam by examining a sender’s record. Blocking spam can help a company save bandwidth, as well as save employees the trouble of combing through unwanted e-mail messages.

“IronPort has a reputation on filtering where they know the reputations of people who are sending e-mails or generating Internet traffic,” said Richard Palmer, senior vice president of Cisco’s security technology group.

“We can use that information at Cisco for the routers and switches and firewalls to filter traffic,” he said.

Cisco said it would pay for IronPort with a combination of cash and stock. The deal is expected to close in the company’s fiscal third quarter, which ends in late April.