Ubunut 9.04 server Concurrent connections limit

[gordlam]

I am a newbie to Ubuntu, actually Linux in general.

I know that Windows XP Pro has a 10-user Concurrent connection limit (simultaneous connections at one time) with an error message of "No more connections" after 10


Does Ubuntu 9.04 server have any Concurrent connection limit ?

and does anyone know if Ubunut 9.04 server complies to Microsoft Networking API ?
this is a requirement for my Autocad and Revit software.

thanks