Netscape's letter does not name the ISPs. --that the company is using its control of the Windows NT operating system to hurt companies, such as Netscape, O'Reilly and Associates, and Process Software, which offer Web servers for NT. Netscape specifically labels as anti-competitive an NT licensing limitation that allows only ten users to connect over TCP/IP networks to servers running NT Workstation 4.0. The letter also states that Microsoft has threatened hardware OEMs that offer NT Workstation bundled with Netscape's Web servers, saying that the OEMs may be in violation of Microsoft ten-user licensing restriction. --that Microsoft has concealed "secret APIs" in Windows NT Server to gain a preferential performance advantage for its own Internet Information Server. --that Microsoft has attempted to "zero out" the markets for Internet servers, tools, and browsers by bundling those products for free with its operating systems.