How to use instreg.exe and instsvc.exe (command line tools for Firebird installation on Windows)

How to use instreg.exe and instsvc.exe

AuthorsOriginal: Alex Peshkov (peshkoff at, Revised by: Olivier Mascia (om at

NOTE :: To solve any potential issues with long paths containing spaces or special (non ascii) characters, these tools no longer take the RootDirectory as a command-line argument. Both binaries must be installed in (or copied to) the /bin directory beneath your Firebird root directory.

(Root directory == directory root where firebird.conf and security2.fdb are installed.)

For example, if they are located in C:\FB20\bin, the root directory will be deduced as C:\FB20.


The purpose of this utility is to install the Registry keys for Firebird. Because its task is to deduce the RootDirectory path as the directory immediately above its own location and to write this to the Registry as an absolute path, instreg.exe must be installed in the /bin sub-directory of the Firebird root directory (see note above).

The Registry key is *not* required for the engine to run; however, many third-party tools expect to read it in order to work. The key stored is

HKLM\SOFTWARE\Firebird Project\Firebird Server\Instances

and contains one string value: DefaultInstance.

This 'DefaultInstance' string value contains the full path (backslash terminated) to the root directory of the installation. This setup is built so that management of named multi-instances of the server will be possible in a next version. Currently, the one and only instance receives the hard-coded

name 'DefaultInstance'. There is nothing else stored in the registry. Any version or configuration information is to be found by third-parties tools in the relevant firebird.conf file. This file can be located thanks to the root path stored in the ...\Instances\DefaultInstance value.


instreg i[nstall]


'-z' can be used with any other option, prints the Firebird software

version as the first line of output.

To get brief text help, just invoke instreg.exe with no arguments.



Firebird provides a standard routine to manage the Firebird Service on WinNT/2000/XP platforms - instsvc.exe.

Console messages

Output of Windows error messages (if any) has been enhanced so that any required transliteration of ansi strings to the OEM charset of the console window is done. This means people using a non-English Windows will get Windows system error messages in their language with correct accents and so on.

Security related features

The '-login' (or -l) option previously implemented has been extensively revised and enhanced. It can now be used to set up the service(s) to run under a specific user account (presumably with limited privileges on the system) instead of the default "LocalSystem".


instsvc i[nstall] [ -s[uperserver]* | -c[lassic] | -m[ultithreaded] ]

[ -a[uto]* | -d[emand] ]

[ -g[uardian] ]

[ -l[ogin] username [password] ]

[ -n[ame] instance ]

[ -i[nteractive] ]


sta[rt] [ -b[oostpriority] ]

[ -n[ame] instance ]

sto[p] [ -n[ame] instance ]


r[emove] [ -n[ame] instance ]


This utility should be located and run from the 'bin' directory of your Firebird installation.


  • '*' denotes the default values

  • '-z' can be used with any other option, prints version

  • 'username' refers by default to a local account on this machine.

  • Use the format 'domain\username' or 'server\username' if appropriate.



assuming Firebird is installed (copied to its installed location).

Superserver and auto-startup are now the default.

instsvc i OR instsvc install

sets up a Superserver as a service in auto-startup (started at boot-up) mode under the default system identity, named "LocalSystem".

instsvc i -g OR instsvc install -guardian

as above, but starts the Guardian service first.

The options "-demand" (-d) and "-classic" (-c) allow the defaults to be changed, so the classic server (instead of the superserver) can be configured as a service and either service can be configured to start on demand instead of starting at boot time.

To remove the service(s)

Services must be stopped before being removed. This could be automated with 3 lines of code

but it is better to leave it as is for safety.

instsvc r OR instsvc remove

removes the service definition. If Guardian was configured, both the guardian and

server services will be removed.

To start and stop the installed service(s)

instsvc sta or instsvc start

starts the server or Guardian + server, according to what was configured by the install command.

instsvc stop

stops the server or Guardian + server, according to what was configured by the install command.


To get a server condition report

This is a new command:

instsvc q or instsvc query

Prints a report of exactly *what* is configured and *how*, as well as whether the services are running or stopped.


To use the secure login feature

Option "-login" requires a username and a password:

instsvc i -g -login user pass

This would configure FB superserver as auto-start, with Guardian, to run under the identity "user" whose password is pass.

* If the password is included, the password should not begin with '-'.

* If the password is omitted from the command-line, instsvc will prompt for it. In that case, the password will be masked with '*' as it is typed.

While configuring the services as above, instsvc automatically grants the Windows operating system privilege named "Log on as a Service" to the specified user. This is required, otherwise the service would not be allowed to start. Instsvc is silent about it unless it fails.

To take care of the possibility that the user logging in via the -login switch might be an ordinary user with no administrator privileges on the machine, instsvc adjusts the default security descriptor of the service(s) so that this user can start/stop/query them.

This is necessary to enable the Guardian (also running as this user) to start the FB server. The user will not be able to uninstall the service(s) nor change their configuration.



Instsvc does not CREATE the "user" on the Windows machine. That would not be a good idea. The admin might want to create the user as part of the local machine or as part of a domain and instsvc has no particular need to usurp the admin's responsibility for creating users.

The user needs to have read/write access to all databases and the firebird.log file. For security reasons, write access to firebird.conf and Firebird executables should NOT be given.

On Windows NT/2K/XP it is common to include the domain or server prefix for a user defined on a domain or locally on another server. In the above examples, "user" might take the form of:

DOMAIN\user or


With no prefix, the user is implicitly a local user on the current machine.