> This service file is on the server or on the client computers?

Both.

The client somehow needs to know which port to use, but the client can't
read that information from the server, so this information is on the
client as well.

E.g. firebird.conf gets installed when the Firebird client software gets
installed.



--
Best Regards,
Thomas Steinmaurer
LogManager Series - Logging/Auditing Suites supporting
InterBase, Firebird, Advantage Database, MS SQL Server and
NexusDB V2
Upscene Productions
http://www.upscene.com