The freetds.conf file

What it does

Just as DNS defines hostnames for network addresses, freetds.conf uses a servername to define the properties of your server. [1] In particular, FreeTDS needs to know:

Primary Server Properties

• Hostname or IP address of the server

• Port number or Instance name (not both)

• TDS protocol version

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. tsql -C reports the sysconfdir to let you confirm it.

In addition, FreeTDS will look for a file .freetds.conf in the user's home directory (${HOME}/.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 file used is the first one that is readable and contains a section for the server.

What it looks like

The following information is also provided in the freetds.conf manual page, cf. man freetds.conf.

The freetds.conf file format is similar to that of Samba's modified "win.ini". It is composed of two types of sections: one [global] section, and a [servername] section for each servername. Settings in the [global] section affect all servernames, but can be overridden in a [servername] 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 = 7.1
					

In this example, the default TDS version for all servernames 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 7.1.

Usually, it is sufficient to state just the server's hostname and TDS protocol version. 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.