Great old April Fools RFC specifies that all new protocols be tunneled over HTTP, in order to evade firewalls and preserve the end-to-end nature of the Internet.
Our methodology is to layer any application layer
Transmission Control Protocol/User Datagram Protocol (TCP/UDP)
packets over the HyperText Transfer Protocol (HTTP) protocol, since
HTTP packets are typically able to transit Firewalls. This scheme
does not violate the actual security usefulness of a Firewall, since
Firewalls are designed to thwart attacks from the outside and to
ignore threats from within. The use of FEP is compatible with the
current Firewall security model because it requires cooperation from
a host inside the Firewall. FEP allows the best of both worlds: the
security of a firewall, and transparent tunneling thought the
firewall.
(via Cryptogram)
