How many client connections does SQL Server 2000 support?
SQL Server 2000 supports 32,767 connections per instance. You can run 16 instances per node, so the maximum number of client connections per server node is 524,272. Note that unless you have SQL Server 2000 Enterprise Edition, you have to pay separately to use each of the 16 instances on one computer.
From an architectural standpoint, if you're planning to provide more than a few thousand connections, you might want to use a middle-tier server such as Microsoft COM+ (Component Services), which comes in the box with Windows 2000, for programs that can use connection pooling to share connections to the database. If your applications are designed and programmed well, you can service more than 30 concurrent users from one connection.