Searching for a quote

Dave Crocker dhc2 at
Mon Mar 16 02:57:59 UTC 2015

On 3/12/2015 5:24 PM, Tom Paseka wrote:
> Be conservative in what you send, be liberal in what you accept
> ^

As with all terse summaries, the meaning of this is easy to distort.
In the unfortunately not-so-uncommon extreme, it is used to argue for
demanding acceptance of all manner of random cruft, essentially
translating into "the protocol requires you to support anything I send you."

This, of course, is not what Jon meant.

Rather, he noted the fact that protocol specifications invariably
contain some ambiguities which, equally invariably, get interpreted
differently by different, reasonable implementers.

Hence the stricture to meant to guide the sending of what an implementer
should consider to be the most conservative interpretations, and accept
the most liberal (different) interpretations.


Dave Crocker
Brandenburg InternetWorking

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