Re: [ietf-smtp] SMTP Greylisting Retry Hints + PRDR

On 2019-02-09 19:39:34 -0500, valdis(_dot_)kletnieks(_at_)vt(_dot_)edu wrote:
> On Sat, 09 Feb 2019 23:38:15 +0100, ?????????? ???????????????? said:
> > if on 250-GREYLIST on retries the IP address of the client is changed, then
> > the Greylist-421-retry=00:00:10 puzzle is not solved and the time begins 
> > again
> > from the beginning on each IP-client-address change.  This is not in the
> > interest of the sender.
> As I mentioned, I don't think it rises to the level of a SHALL - that's 
> usually
> reserved for things where failure to do so causes a high risk of the protocol
> failing to work properly.
I also think a SHALL is inappropriate here on purely formal grounds: An
extension is by definition optional. A client may or may not implement
it. Putting a mandatory requirement on a client which hasn't yet
indicated that it supports the extension is therefore impossible.

Just stating that keeping the values in the triple constant (or at least
restricting their range) will improve the chances of a speedy delivery
is IMHO preferrable to stating a specific requirement.

        hp

-- 
   _  | Peter J. Holzer    | we build much bigger, better disasters now
|_|_) |                    | because we have much more sophisticated
| |   | hjp(_at_)hjp(_dot_)at         | management tools.
__/   | http://www.hjp.at/ | -- Ross Anderson <https://www.edge.org/>

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