Viktor Dukhovni:
>
>
> > On Dec 5, 2017, at 10:24 PM, J Doe <gene...@nativemethods.com> wrote:
> >
> > That actually reminded me of something that crossed my mind, today - I
> > forgot about the inherently dynamic nature of routing.
> >
> > Even though my server is within North America and it is extremely likely
> > that I am hitting the closest node of Google?s GMail servers in North
> > America, as routes are updated over time, there?s the possibility of the
> > mail going over a poor connection in a worst case scenario.
> >
> > I know that?s less likely given the North American scenario, but it helped
> > me understand even more why this setting would not be enabled by default.
>
> Note that distance alone would not typically cause any problems here,
> the deadline time is applier per *line* from the client, whether an
> SMTP command, or line of body content, and Postfix limits such lines
> to 4096 bytes (storing partial lines in the queue file as needed to
> support longer logical lines).
>
> So to fail the deadline timer a sender would have to be unable to
> deliver 4096 bytes in ~300s (no stress) or 10s (stress). Either
> way, that's enough time to stream 4k from the Moon at any plausible
> bandwidth. I don't think that deadline timers are nearly as risky
> as one might conclude from the disclaimers, it is just that they have
> not been as widely tested, so operational experience is limited.
With TLS turned on, the deadline is enforced per TLS message, which
can be up to 16kbytes. 16kbytes in 10s would be difficult with a
dialup or low-tech cellular network.
Wietse
Wietse
