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| Internet layer |
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The Quote Of The Day (QOTD) service was a method used by mainframe sysadmins to broadcast a daily quote on request by a user. It was formally codified both for prior purposes as well as for testing and measurement purposes in Internet protocol RFC 865[1].
A host may connect to a server that supports the RFC 865 QOTD protocol, on either TCP or UDP port 17. In order to keep the quotes at a reasonable length, RFC 865 specified a maximum length of 512 characters for the quote.
Although some sources indicate that the QOTD service is rarely enabled, and is in any case often firewalled to avoid 'pingpong' attacks.[2], interest continues in the pre-existing purpose of serving quotes as can be seen with web engine searches. As is indicated in RFC 865, the QOTD concept predated the testing and measurement purposes ascribed to QOTD in that protocol.
Current testing and measurement of IP networks is more commonly done with ping and traceroute, which are more robust adaptations of the echo protocol, specified in RFC 862[3] which predated the attempt at QOTD standardization.