postcard protocol

idea: m455
implementation: acdw

the 'postcard protocol' is a dummy simple way of sending messages to friends.
basically, you have a little postcard that you send over udp to your friend who has a mailbox running.
their mailbox listens for packets of up to 512 bytes long, and when it receives one, it prints it.

that's it ... for now.

oh, the port is 42069 for the time being and uh, it's just over localhost byeeeee

(for a description of the protocol, see <https://git.acdw.net/postcard/tree/protocol.txt>)

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programs

server, listens to ports and handles incoming postcards: postoffice

client:
- send:  postcard
- check: postbox
- admin: postmaster