The maximum number of worker thread for each Internet protocols is by default 40. Using notes.ini you can modify the worker threads for each protocol
LDAPMaxWorkerThreads=#
SMTPMaxWorkerThreads=#
IMAPMaxWorkerThreads=#
POPMaxWorkerTreads=#
DIIOPMaxWorkerThreads=#
HTTPMaxWorkerThreads=#
Note: that HTTP is currently the only protocol where worker threads can be set in the server document.
