A server is a process that is waiting for other (client) processes to connect to it. As such, a server communication end-point needs to be made known to client processes.
One type of end-points use a network address/port number combination. For example, 192.168.3.25:80 specifies the communication end-point to be port 80 at the interface 192.168.3.25. This module does not assume any knowledge of TCP/IP networking, so this form of end-point specification (mostly for networking purposes) will not be discussed in details.
Another type of end-points use a named “socket” in the file system. A named socket is an entity in the file system. It has an inode associated with it, along with a path. Compared to the IP address+port number approach, a named socket is only useful if both the server and client processes share the same file system.