I am using Firebird server on a Debian 9 stretch on a Virtual Box machine and FlameRobin client on another Windows 7 VM for testing.

There is no firewall activated.
I can access the database locally using isql-fb.

I have installed Firebird 3.0 via Debian oficial packages:
# apt-get install firebird3.0-server

And I have changed SYSDBA password:
# dpkg-reconfigure firebird3.0-server

And I have changed SYSDBA password via isql-fb:
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https://firebirdsql.org/file/documentation/reference_manuals/user_manuals/Firebird-3-QuickStart.pdf
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In this example, the “employee” example database is used,
because its alias is always present in a freshly installed Firebird setup:
#isql-fb
connect localhost:employee user sysdba password masterkey;

If you do this in isql, it should respond with:
#isql-fb
Database: localhost:employee, User: SYSDBA

Now alter the sysdba password:
#isql-fb
alter user sysdba set password 'Zis4_viZuna83YoYo';
-------------


# cat /etc/debian_version
9.0
# firebird -z (via apt-get install firebird3.0-server)
Firebird TCP/IP server version LI-V3.0.1.32609 Firebird 3.0

I have added the following to /etc/firebird/3.0/firebird.conf
------------
DatabaseAccess = Full
RemoteAccess = True
UdfAccess = Full
AuthServer = Legacy_Auth, Srp, Win_Sspi
AuthClient = Legacy_Auth, Srp, Win_Sspi
UserManager = Legacy_UserManager, Srp
Providers = Remote,Engine12,Loopback
WireCrypt = Enabled
WireCompression = True
RemoteServicePort = 3050
ServerMode = Super
------------




I am using Flamerobin 64 bits and Firebird Client 64 bits (fbclient.dll version 3.0.2.32703) on the same FlameRobin's folder on another VM with Windows 7 Profissional 64 bits:
---------------------------
About FlameRobin
---------------------------
FlameRobin 0.9.3 (git hash 5ece15b) Unicode (x64)
Database administration tool for Firebird RDBMS

This tool uses IBPP library version 2.5.2.1
wxWidgets library version 2.8.12
and Boost library version 1.54.0
---------------------------




I can ping and access Samba from Windows VM to Debian Linux VM, but I can't access Firebird 3.0:
---------------------------
Unhandled Error in FlameRobin
---------------------------
*** IBPP::SQLException ***
Context: Database::Connect
Message: isc_attach_database failed

SQL Message : -902
can't format message 13:98 -- message file C:\Program Files\FlameRobin (x64)\firebird.msg not found

Engine Code : 335544721
Engine Message :
Unable to complete network request to host "192.168.100.100".
Failed to establish a connection.
---------------------------

What am I missing?