Most modules and constants have been renamed. In most cases, the new names involve some variant of “firebird” or “fb”. For example, the API library is now located in a shared library named “fbclient.dll” on Windows and “libfbclient.so” or “libfbembed.so” on other platforms.

The exception that breaks the rule is the security database, formerly named “isc4.gdb”, which is now called “security.fdb”.

External files used by the server (UDF libraries, BLOB filters, character set libraries, external tables) are now subject to levels of filesystem protection that, in some cases, default to a level that will be different to what you had under Firebird 1.0.x or InterBase.

The new server configuration file, firebird.conf, that replaces ibconfig (Windows) and isc_config (other platforms) contains several new configurable features along with improved self-documentation and organisation.

A database-aliasing feature comes in 1.5. Now you can optionally “soft-code” the database location into your application code using your choice of alias to replace the path string. Actual path locations are stored in a text file, aliases.conf. The main purpose of aliasing, however, is to protect your physical paths from being maliciously “sniffed” on the wire.

The default (and past practice) on Windows server platforms makes it that the localsystem user runs the program that installs the Firebird service at system start-up. This could be a serious security vulnerability if the Firebird server should be hacked, since it provides a window through which the hacker can access the entire machine. The 1.5 version of this program (instsvc.exe) now accepts a Windows user log-on for the service installation. It is strongly recommended that you create a Firebird user for this purpose and make use of the new logon feature if your server is connected to the Internet in any way.