On Nov 30, at 10:18, Mirko Thiesen vomited up this:
> On Tue, 30 Nov 2004, Colin J. Raven wrote:
>
> > Sorry about this, it's a test to send some list traffic to my box.
> >
> > My mail server is suddenly bouncing mail from this list, and the list
> > has also abrubtly stopped accepting mail from my server claiming a
> > greylisting issue. Weirder still during the past 24 hours (when this
> > first started happening) I haven't done anything to the box....anything!
> >
> > Oddly the mail logs stated something to the effect that my message had
> > been rejected because it had been greylisted for 300 seconds...and to
> > "try again later". That's sort of illogical somehow. You're either
> > rejected or else you 'aint (so to speak).
>
> Although I do not know why you are unable to receive mail from this list,
> what you describe is exactly what greylisting does. The purpose is to
> reject an incoming mail _temporarily_. Most spam bots will not bother to
> retry sending the message and simply move on to the next victim whenever
> they encounter any kind of failure. Your MTA should be able to distinguish
> between a hard bounce (5xx) and a soft bounce (4xx), which is what
> greylisting leads to. A hard bounce usually indicates a permanent failure,
> so the sending MTA should not attempt any further deliveries, whereas a
> soft bounce indicates that the reasons for not accepting the mail are of a
> temporal manner. Thus, your MTA should try to deliver your mail again
> after a defined period of time. Having put "you" into a database, the
> receiving MTA knows "you" when your MTA eventually commences another
> delivery attempt - if the time span between your retries lasts for at
> least what the receiving MTA forces as a limit between deliviery attempts.
> This is to prevent circumvention of the greylisting system by simply
> hammering the receiving MTA with subsequent delivery attempts.
>
> To put it short: You should not have to take any special actions in order
> to send mail to the list. The fact that your message was distributed by
> the list showes this, by the way. ;-)

Your comments are noted and I'm in complete agreement with what you
said. I wasn't tweaking to get rid of greylisting for such is not
possible of course.

Last night I couldn't post to the list - just no way. My IP was being
rejected...not *just* greylisted. In *addition* to that I couldn't
receive anything, my box was giving out "451 Server configuration
error(s) *and* "554 Error: no valid recipients" which is totally absurd.
Thinking that (somehow) Postfix had lost its marbles I reloaded it - not
once but several times. When that made no difference I rebooted the box
(more in frustration than anything else). That made no difference
either. Finally, seeing my logs jusy filling up with the same nonsense
repeatedly I powered down the box and went to bed.

This morning I restarted the box and everything seemed back to normal.
There was one exception, a list that I recently subscribed to was being
rbl-rejected. I commented out all the rbl-reject stuff in postfix
main.cf, reloaded once again and finally *everything* was back to
normal. This was odd behavior indeed since the rbl-reject entries have
been in main.cf for some 3 weeks now with no ill effects (just a whole
lot less canned ham).

I'm at a complete and total loss to explain this transient phenomenon.
It's distrurbing precisely because it *is* transient. It's like making
an appointment to see the doctor for a pain in your [shoulder] only to
find, upon arrival at the office, that the pain has vanished and
subsequently doesn't return. I expect that from the body, but such
behavior is somewhat less frequently observed in the predictable stable
world of NetBSD (and in this case Postfix).

Patience of fellow list subscribers has been greatly appreciated while
this [non] topic was purged from my brain - by uploading the entire
thought process to the list. Now back to our regularly scheduled
broadcast.

Regards to one and all,
-Colin