nanog mailing list archives

Re: Searching for a quote


From: Michael Thomas <mike () mtcc com>
Date: Fri, 13 Mar 2015 00:17:02 -0700

On 03/12/2015 11:52 PM, Eygene Ryabinkin wrote:
Thu, Mar 12, 2015 at 05:31:54PM -0700, Michael Thomas wrote:
Jon Postel. I'm told that it is out of favor these days in protocol-land,
from a security standpoint if nothing else.
The principle has nothing to do with security: it doesn't mean "accept
all junk that comes in".  It is about interoperability of different
implementation and means "use the smallest possible subset of the
protocol when you're sending, but be prepared to accept any subset
of protocol messages when you're receiving".  Eric Allman's ACM paper,
   http://cacm.acm.org/magazines/2011/8/114933-the-robustness-principle-reconsidered/fulltext
is a good reading for this, I believe.

The original principle had little thought toward security, and i was there for the row for which Eric's paper was almost certainly inspired by (started it, actually). In the early days, a lot of people to took it as trying very hard to make sense of the broken -- far beyond rfc 2119's musts and shoulds. A lot of people regret that now for a lot of reasons, including security. I still have mixed emotions about abandoning it.

Mike


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