The format of the interfaces file is borrowed directly from that used by Sybase on Unix platforms (Windows™ has a different format). Additionally, we have overloaded one of the fields to add the ability to set the protocol version. An example interfaces file looks like this.
Example B.1. An interfaces file example
myserver query tcp 4.2 127.0.0.1 4000 master tcp ether 127.0.0.1 4000
The entry starts with the servername beginning in the first column (no whitespace preceding it). Following the servername are one or more services lines which must be indented with whitespace. FreeTDS™ uses only the query line, although others may be present to retain compatibility with Sybase.
The fields in the services lines are as follows.
Table B.1. Services Line
| Name | Example | Meaning |
|---|---|---|
| service | query | The only supported service |
| transport | tcp | The transport protocol to use. Only tcp is supported by FreeTDS™. |
| physical | 4.2 | Historically this field referred the physical/datalink layer, however it appears to simply a comment field. Therefore, FreeTDS™ optionally uses it to specify the protocol version to connect with. |
| hostname/IP | 127.0.0.1 | The hostname or IP address where the SQL Server™ resides. |
| port | 4000 | The TCP port where the SQL Server™ is listening. |
In the example above, the hostname was entered as an IP address. It needn't be; it could just as well be a name. FreeTDS™ can use a name rather than an address; it will just let the network (specifically, the resolver get the address.