3.3. Installing multiple servers

Firebird allows the operation of multiple servers on a single machine. It can also run concurrently with Firebird 1.x or InterBase servers. Setting this up is not a beginner’s task though. If you need to run multiple servers on the same machine, the second and subsequent servers must be installed and configured manually. They need to have different service names and should listen on different TCP/IP ports. The file install_windows_manually.txt in the doc subdir may be of help if you’re doing this on Windows, but bear in mind that it was written for Firebird 2.1.

Also read the chapter Configuring the Port Service on Client and Server in the Firebird 1.5 (!) Release Notes:

https://www.firebirdsql.org/file/documentation/release_notes/html/rlsnotes15.html#config-port
https://www.firebirdsql.org/file/documentation/release_notes/Firebird-1.5.6-ReleaseNotes.pdf#page=96