alphaolomi/index.md

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    Quote of the Day


from https://www.gkbrk.com/wiki/qotd_protocol/

Tags: networking protocol
Quote of the Day is a simple protocol that is used to deliver daily quotes. Although its usage is almost nonexistent these days, there are still a few public servers. The protocol is defined by RFC 865. According to the RFC, a QOTD server is run on port 17 for TCP and UDP connections.
The RFC recommends that;

The quotes should be limited to the ASCII printable characters, spaces and newlines.
They should be less than 512 characters.

Since the protocol is only used to send quotes to terminals, these aren’t hard requirements. But a server should still follow these recommendations in order to be compatible with the other servers and clients.
Despite the name being Quote of the Day, a server does not have to serve daily quotes. It can change the quote at any interval or send random quotes at each connection.
TCP Connections

When a QOTD server gets a connection, it sends a quote and closes the connection, discarding any received data. Basically, a server should do the following
Listen to connections on port 17.

Accept a connection.
Choose a random quote.
Send the quote to the client.
Close the connection.

UDP Connections

A UDP server is a bit different from a TCP one. Since UDP has no concept of connections, a server just sends the quote after getting a UDP datagram.
Listen to UDP datagrams on port 17.

When you get a UDP packet:
Discard any data in the packet.

Send a UDP datagram containing the quote back to the client.
Public QOTD Servers


Server Address
TCP Port
UDP Port


djxmmx.net	17
17


cygnus-x.net
17
17


## main.py
import socket
import random

quotes = [
    "Never do today what you can do tomorrow",
    "Nobody lies on the internet",
    "The cake is a lie"
]

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("0.0.0.0", 17)) # Bind to port 17
server.listen(5)

while True:
    sock, addr = server.accept()
    quote = random.choice(quotes)
    sock.send(f"{quote}\n".encode("utf-8"))
    sock.close()
	import socket
	import random

	quotes = [
	"Never do today what you can do tomorrow",
	"Nobody lies on the internet",
	"The cake is a lie"
	]

	server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	server.bind(("0.0.0.0", 17)) # Bind to port 17
	server.listen(5)

	while True:
	sock, addr = server.accept()
	quote = random.choice(quotes)
	sock.send(f"{quote}\n".encode("utf-8"))
	sock.close()