Networking Essentials easy
Which standard protocol listens on Port 22?
- A HTTP (Hypertext Transfer Protocol), used for the unencrypted delivery of standard web pages and static assets from a central server to a browser.
- B SSH (Secure Shell), used for establishing encrypted remote administration sessions and secure file transfers between a client and a command-line interface.
- C DNS (Domain Name System), used for translating human-readable domain names into the machine-readable IP addresses required for network routing.
- D SMTP (Simple Mail Transfer Protocol), used for the reliable transmission and relaying of outbound email messages between various disparate mail servers.
Answer: B. SSH (Secure Shell), used for establishing encrypted remote administration sessions and secure file transfers between a client and a command-line interface.
Ports are used to distinguish between different services running on a single server. By convention, certain ports are 'well-known' and reserved for specific protocols. SSH (Secure Shell) defaults to port 22 to provide a secure channel for remote system management. For comparison, HTTP uses port 80, HTTPS uses port 443, and DNS uses port 53. While administrators can change these defaults for 'Security via Obscurity' (making it slightly harder for bots to find the service), standardizing on port 22 ensures that administration tools can connect without manual port configuration.
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