In that case, I'd first ping your subnet, then try to connect to the firebird port (3050 TCP by default, IIRC) to see if something (e.g. Firebird) is listening.
HOWEVER, why don't you just use a config file with the server IP address/hostname? An admin will have to set up a Firebird server anyway?
computer [...] where current and active database file is stored (firebird)
Note: FYI: if using Firebird for multiple users, you're supposed to use a server, not a file share with an fdb file on it and e.g. multiple embedded client. You may get data corruption, locking etc. Just thought I'd mention it.