RFC 862

Echo Protocol 🦋

okay bestie, this is RFC 862 💖 and it's giving classic ARPANET energy. It was written by J. Postel at ISI and dated May 1983. The category is a standard for the ARPA Internet community 👑, and the header doesn't list anything it obsoletes or updates, so it's a clean slate 🧚

Hosts on the ARPA Internet that choose to implement an Echo Protocol are expected to adopt and implement this standard ✨

An echo service is lowkey the most useful debugging and measurement tool ever 🙈 Its whole thing is that it sends back to the originating source any data it receives. So you send data in, it bounces right back to you. Iconic 💅

TCP Based Echo Service 🌸

okay so the first flavour is a connection based application on TCP 💜 A server listens for TCP connections on TCP port 7. Once a connection is established, any data received is sent back. This keeps going until the calling user terminates the connection. main character energy 👑

UDP Based Echo Service 🫶

and the second flavour is a datagram based application on UDP 🌈 A server listens for UDP datagrams on UDP port 7. When a datagram is received, the data from it gets sent back in an answering datagram. no cap, it's the same bounce-back idea, just with datagrams instead of a connection 🎀