Ich habe mal wieder etwas ins Internet geschrieben, diesmal zum Thema #Debian und #Firebird.

https://www.dirk-hagedorn.de/?p=2231

#Gefrickel

Firebird auf Debian 13 (Trixie) – Dirk Hagedorn

@hgdrn The Firebird client library *also* reads firebird.conf, and uses its `RemoteServicePort` setting as its default port. See also https://firebirdsql.org/file/documentation/html/en/refdocs/fbconf/firebird-configuration-reference.html#fbconf-firebird
Firebird Configuration Reference

@hgdrn And, yes, this can be surprising. I think it was implemented with an assumption that clients don't generally load the same library as the server (and thus either have their own configuration, or the "unconfigured" defaults). On Windows, that assumption usually holds even on the same machine (though not for tools like ISQL), on Linux less so.
@hgdrn But the mismatch in defaults between the installation running on port 3050, and the tools using a configuration with port 3051 is on Debian.