Hi,

telephone and email support are only available to Allegro/Presto/Vivace users; send a mail to info@lightstreamer.com for further info.

As per your question the answer is yes.
(there are exceptions e.g. lightstreamer servers behind a load balancer with sticky capabilities, but even in those cases at the end the server is in a way or the other exposed on the internet or on the intranet if that's the case).