> From: Greg Skinner <gds@xxxxxxxx>
> It seemed like a reasonable thing to do to treat something like a net
> or host unreachable as a transient condition ...
> However, this practice doesn't seem to have made it into the
> application-writing community at large, because lots of applications
> fail for just this reason.
Then they are violating an explicit MUST in RFC-1122 ("Requirements for
Internet Hosts -- Communication Layers", October 1989), which says:
18.104.22.168 Destination Unreachable
A Destination Unreachable message that is received with code 0 (Net), 1
(Host), or 5 (Bad Source Route) may result from a routing transient and
MUST therefore be interpreted as only a hint, not proof, that the specified
destination is unreachable
This problem (people interpreting Unreachables as hard errors) was a problem
back then, 20 years ago, which is why we put that text in the RFC.
> I wonder if even writing a BCP about this even makes sense at this
> point, because the application writers (or authors of the references
> the application writers use) may never see the draft, or even be
> concerned that it's something they should check for.
I agree that it may be a waste of time, because they are *already* disobeying
an explicit requirements RFC.
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