Read here about connection strings: https://firebirdsql.org/file/documentation/reference_manuals/user_manuals/html/qsg3-databases.html
Run "Command prompt" and enter command: >ping FIREBIRDSERVER If 'ping' command failed - use an IP address instead: >ping xxx.xxx.xxx.xxx If succeeded - use IP instead 'FIREBIRDSERVER' in connection string Additionally. As I understand, your Firebird server is installed on Windows ('FIREBIRDSERVER'). By default "Windows Firewall" blocks incoming connections from network. Open 'Windows Firewall', create 'inbound' rule to allow connections to TCP port 3050 from LAN. Watch this my video how to install and configure Firebird on Windows: http://rgho.st/private/6xRXbzJqH/4d0ee11d53c142ea2590e648bc363f8f (It is about installation one of our applications, so you can skip second half of video) 8 липня 2019, 14:32:48, від "Tony Christiansen t...@adegroup.com.au [firebird-support]" <firebird-support@yahoogroups.com>: Hi Rustam Where is an explanation of the different connection strings. I am using a TIBDatabase in Delphi With databasename property set to \\FIREBIRDSERVER\E:\DB.FDB it connects With databasename property set to FIREBIRDSERVER:E:\DB.FDB it does not connect with error unable to complete network request to host "FIREBIRDSERVER" My environment is windows and without the \\ the client cannot find the host. Thanks for your assistance Tony