An interfaces file contains information about the network locations of servers.
In the Sybase client/server environment, a client can connect with Adaptive Server if it knows where the server resides on the network and if the server supports the client’s language or character set. When a client initiates a connection, it looks in its interfaces file for the network location of the target server.
The interfaces file lists the name and address of every server, including Backup Server. When you are using a client program, and you want to connect with a particular server, the client program looks up the server name in the interfaces file and connects to that server. You can also supply the name of the server by using the DSQUERY environment variable.
Servers also need network information. When a server starts up, it looks in its interfaces file to determine where to listen for client connection requests. In addition, Adaptive Server can take on a client role when it makes remote procedure calls to other Adaptive Servers.