Microsoft will post a beta version of IIS 4.0, formerly code-named K2, on its site for free downloading later this week, said Tanya van Dam, a group product manger at Microsoft. Testing of the new IIS begins a week after Microsoft learned that an earlier version of the server, IIS 3.0, is vulnerable to "denial of service" attacks that could crash a Web site.
Late last week, users exploited the vulnerability to repeatedly bring down Microsoft's own, heavily trafficked site. Microsoft posted a patch for IIS 3.0 over the weekend. Van Dam said that IIS 4.0 would not be vulnerable to the same denial of service attack.
Microsoft has taken other steps to ensure the stability of Web sites running on IIS 4.0. The server includes crash protection so that if one Web application goes down it doesn't bring the entire site to a screeching halt. Crash protection was possible before, but only after considerable programming, van Dam said.
IIS 4.0 also includes a feature that could help Microsoft make further inroads with Internet service providers and large Web sites, many of whom rely on the freeware Apache server. The feature allows a single Web server to easily host multiple sites--for example, cnet.com, news.com, and dozens of others.
Hosting multiple sites was possible, but difficult, with earlier versions of IIS, van Dam said. The feature has contributed to the popularity of Apache, which accounts for 44 percent of the Web servers on the Internet, according to a June survey by software consultants Netcraft.
Besides Apache, Microsoft is also competing directly with Netscape Communications' recently released Enterprise 3.0 server. Following a similar strategy with its Internet Explorer browser, the software giant has attempted to undercut the $995 Enterprise server by offering IIS as a free add-on to its Windows NT Server operating system.
With its huge stockpile of cash, Microsoft can afford to giveaway its Internet software in order to gain market share. Netscape, on the other hand, is becoming increasingly dependent on server sales. Last quarter, server sales accounted for 37 percent of its overall revenue.
Van Dam declined to discuss whether Microsoft would continue to offer IIS 4.0 for free. She said that the company has no plans to offer IIS for Unix, still an extremely popular operating system for running Web sites. A final version of IIS 4.0 will be available in the fall.
IIS 4.0 will also include the following features: