The interfaces file contains information about the network locations of servers.
Open Client and Open Server use interfaces as a limited-function directory service. The interfaces file also serves as a default if an external directory service fails.
Open Client uses the network information provided by the query line of an interfaces entry to connect to the server.
Open Server uses the network information provided by the master line of an interfaces entry to listen for client connection requests.
The interfaces file is created during installation as $SYBASE/interfaces. Open Client and Open Server products look for interfaces in $SYBASE.
An application can look for interfaces in a location other than the default location. For more information, see ct_config in the Open Client Client-Library/C Reference Manual and srv_props in the Open Server Server-Library/C Reference Manual.