Xinetd (Extended Internet Services Daemon) refers to a super-server daemon for Linux and UNIX-based systems. It’s a service that is designed to “stay awake”, listen for requests, and then start or stop the required services or daemons. These services might include things like the Telnet, FTP, or POP3 protocols, which users connect to over a network. Once the service is idle and no longer needed, Xinetd can stop it to conserve system resources.
How Xinetd is used
- Access control. It enables administrators to restrict network services by various criteria like source IP address, destination IP address, or time of access.
- Logging and monitoring. Not only does it log all the incoming requests, but it can also be configured to log additional information.
- Service management. It starts services on demand, which can conserve system resources. When a service is idle, Xinetd stops it.
What services Xinetd handles
- FTP (File Transfer Protocol). It’s used for transferring files over a network.
- SSH (Secure Shell). A protocol for securely accessing remote systems.
- SMTP (Simple Mail Transfer Protocol). It’s the standard protocol for sending emails.
- HTTP (HyperText Transfer Protocol). The standard Web protocol, often used for serving websites.
- POP3 (Post Office Protocol 3) and IMAP (Internet Message Access Protocol). These are used for retrieving emails from a server.
- DNS (Domain Name System). It’s a service for converting human-readable domain names into numerical IP addresses that computers can understand.