According to Stamford, Conn.-based analyst firm Gartner Inc., eBay's purchase of Skype could result in a product more suited for corporate use.

In the meantime, business users should refrain from using "voice services based on proprietary protocols like Skype while on corporate networks because of network security issues," Gartner said in a Sept. 15 advisory.

There are several reasons for the concern, industry experts said.

"Skype is VoIP on steroids," capable of punching holes through many of the network defenses that companies typically deploy, said Tom Newton, product manager at SmoothWall Ltd., a Leeds, England-based vendor of firewalls and other security products.

Like other P2P technologies Skype allows users to establish direct connections with each other. It's also "port agile," meaning that if a firewall port is blocked Skype will look around for other open ports that it can use to establish a connection, Newton said. "If you put Skype behind a firewall or Network Address Translation layer, 99 times out of 100 it will work" without any special configuration, he said.