Enterprise Ready Server is based on version 2.0 of Apache and comes with new support for Microsoft's Active Server Pages (ASP.Net) development platform.
Previously, ASP.Net applications could only run on Microsoft's Internet Information Server (IIS), a competitor to Apache.
As a result, Covalent said that many major Apache users, such as Morgan Stanley Dean Witter and Bear Stearns, have used both IIS and Apache to accommodate various Web applications designed inside their organisations.
"They can now consolidate their applications on a single platform," said Jim Zemlin, vice-president of marketing at Covalent.
Developers will also be able to write applications for Apache 2.0 using Microsoft's Visual Studio .Net development tools, he said.
Apache is the most widely used Web server on the Internet, according to a survey from Netcraft. Many users choose the technology over IIS because of its superior reliability and security, said Stacey Quandt, an analyst with Giga Information Group.
With help from Microsoft, Covalent said it was able to develop a module for its Enterprise Ready Server that would allow ASP.Net applications to run on Apache 2.0.
However, organisations that use the freely available Web server will not be able to run ASP.Net applications unless they purchase Covalent's software. Zemlin said the company was not planning to release an open source version of its .net module.
Brian Behlendorf, president of the Apache Software Foundation and one of the original authors of the technology, said that Covalent's work adding support for ASP.Net applications bodes well for the future of Apache, even if the software was not free to Apache users.
Behlendorf noted that Covalent employs a number of developers who contribute to the Apache open source project.
"It's a business model we support," he said. "We want to encourage companies to stay in business so they can contribute to Apache."
The added support for Apache comes one day after Microsoft announced that it would extend its .net platform to work with database software from Oracle.
"This is just another example of how Microsoft is working with other application vendors to make .net interoperable with other platforms," Zemlin said.