Because the protocol is independent of application protocols, it can be (and has been) used for many different services, such as telnet, FTP, finger, whois, gopher, WWW, etc. Access control can be applied at the beginning of each TCP session; thereafter the server simply relays the data between the client and the application server, incurring minimum processing overhead.
Due to its detachment from specific applications, it has been applied to numerous services including telnet, FTP, finger, whois, gopher, WWW, etc. Access control can be implemented at the onset of each TCP session; thereafter the server functions as a conduit, transmitting data between the client and application server with minimal processing demands.