The freetds.conf file

What it does

FreeTDS uses a configuration file freetds.conf (the name can be controlled by an environment variable). Its format is similar to Samba's modified "win.ini" format. Its foremost job is to relate dataserver names, as known to your programs [1] , to machine names, as known your network. That is, while your machines have names known to the network, the dataservers on your machines have names known only to your FreeTDS client programs. The configuration file can then further describe that dataserver in greater detail, as need be.

FreeTDS also supports an older configuration file format, known as the interfaces file. Use freetds.conf unless interfaces is needed for your situation. It is easier to read, and it is where all the new options are being added. FreeTDS looks for freetds.conf first, falling back on interfaces only if freetds.conf is not found. Should you need it, more information about interfaces can be found in the Appendix.

Where it goes

The default location of freetds.conf is determined by the --sysconfdir option of configure. If you don't specify anything, configure's default sysconfdir is /usr/local/etc.

In addition, FreeTDS will look for a file .freetds.conf in the user's home directory (~/.freetds.conf).

The actual name and location of freetds.conf may be specified by the environment variable FREETDS (or FREETDSCONF, same effect). See Environment Variables, below.

FreeTDS reads the user's ${HOME}/.freetds.conf before resorting to the system-wide sysconfdir/freetds.conf. The first properly configured (i.e., a readable file with a section for the server) freetds.conf file will be the one used.

What it looks like

The freetds.conf file is composed of two types of sections: a [global] section, and one [dataserver] section for each dataserver. Settings in the [global] section affect all dataservers, but can be overridden in a [dataserver] section. For example

[global]
	tds version = 4.2

[myserver]
	host = ntbox.mydomain.com
	port = 1433

[myserver2]
	host = unixbox.mydomain.com
	port = 4000
	tds version = 5.0

[myserver3]
	host = instancebox.mydomain.com
	instance = foo
	tds version = 8.0

In this example, the default TDS version for all dataservers is set to 4.2. It is then overridden for myserver2 (a Sybase server) which uses 5.0, and myserver3 (a MSSQL 2000 server) which uses 8.0.

Note that myserver3 uses a named instance configuration, instead of a port number.

Usually, it is sufficient to state the only server's hostname and TDS protocol. Everything else can be inferred, unless your setup (or your server's) strays from the defaults.

Some people seem to feel safer using the IP address for the server, rather than its name. We don't recommend you do that. Use the name, and benefit from the inherent advantages. That's why DNS was invented in the first place, you know.

It bears mentioning here that prior versions of FreeTDS were quite fussy about domain logins, forcing users to make explicit per-server entries in freetds.conf. That is no longer the case. If the username has the form DOMAIN\username, FreeTDS will automatically use a domain login.