I am fascinated by these 6 obsolete internet protocols, all written up as seperate RFCs by Jon Postel in May 1983. They are hilariously simple. (Which I mean as a compliment; their simplicity inspires me.) Several of the RFCs are less than one page long:
|Character Generator Protocol||19||864|
|Quote of the Day Protocol||17||865|
|Active Users Protocol||11||866|
My favorite of the above is Quote of the Day (QotD) Protocol. It's like Twitter for teletypes! Send any packet to port 17, and it responds with whatever message the system administrator wants, up to 512 characters.
Sadly QotD and the others are nearly/totally extinct today because of security. Everything I read about QotD warns that it was insecure. For example, this document by the Irish government on QotD says:
An Internet Accessible QOTD Service can be abused for a Distributed Denial of Service (DDoS) Reflection/Amplification attack against a third party.
I don't understand why. I can see how the UDP version of the service (which the RFC specifies) is insecure. As UDP is a connection-less protocol that does not validate source IP addresses, it can be turned against someone. But how was the TCP version insecure? Or was it?
Is insecurity the real reason they became extinct? Honestly, they seem mostly useless...could that be the real reason?
A few still run:
djxmmx.netruns Quote of the Day Protocol
time.nist.govruns Daytime Protocol
Are these relics insecure? Have they modified the spec in some way to become more secure?