Microsoft gained nearly five percent market share in the Web server market, however still lags well behind market leader Apache, research and security firm Netcraft said Friday. Nonetheless, it was the biggest one-month swing in the history of the industry.

With more than 80 million Web sites on the Internet, Microsoft now claims a 25.2 percent share, up 4.7 percent from March. Apache still leads by a wide margin, however it was down close to 6 percent to 62.7 percent. Sun remained a distant third, down slightly to 2.36 percent.

Much of the Redmond company's gains have to do with registrar GoDaddy's decision to migrate its 3.5 million hostnames to the Windows platform. It had formerly been the world's largest Linux host, and now is the largest Windows Server 2003 host as a result of the switch.

A little under a million hostnames have still not been migrated to Windows as of yet, which means Microsoft will likely see another significant increase of a percentage point or two due to its deal with the registrar.

Microsoft has been able to increase its share dramatically in the past as well. It was given a boost during 2001 and 2002 when Register.com and VeriSign announced their migration plans. Also, shortly before GoDaddy made its switch, another large registrar, enom, also announced plans to move to Windows Server 2003.

"Technology trends among registrars have a large impact on Web server market share, as each registrar hosts large numbers of parked domains," the firm explained.

There is still space for Microsoft to continue increasing share, according to the survey. Netcraft noted that major registrars 1&1 Internet, Dotster and Register.com host on Linux, while Network Solutions uses Solaris.