Re: 1. Re: Ordinary user account can't log in; 2. Greylisting

["Jay F. Shachter" <jay%m5.chicago.il.us@localhost>]

Centuries ago, Nostradamus predicted that Greg Troxel would write on Wed Oct 9 07:41:52 2024:

> 
> "Jay F. Shachter" <jay%m5.chicago.il.us@localhost> writes:
> 
>>
>> Unrelated to the above -- I sent this message hours ago to the mailing
>> list, and the SMTP server at mail.netbsd.org sent me back a 450 error
>> because it was greylisting me, which I only noticed a few minutes ago.
>> I think it is moronic to greylist people who are on the netbsd-users
>> mailing list.  Is there any empirical reason why this is being done?
>>
> 
> Separately from the technical points addressed by martin@, it's rude
> to call this moronic.  Setting aside that it is well understood by
> anyone who has run a mail system that spam filtering is complicated
> and challenging, it's unprofessional language.
> 

You are right.  It is unprofessional language.  Moreover, inasmuch as
I do my own mail filtering (although I do not do my own greylisting),
I should be aware of, and more sympathetic to, the difficulty of
getting it right the first time (I even have some funny stories I
could tell about that, and am resisting the temptation to do so).  I
publicly apologize for publicly proclaiming that "it is moronic to
greylist people who are on the netbsd-users mailing list".

Two other people made comments to which I should respond.  One
considered it likely that I was sending mail in multipart/alternative
format.  I am not.  I generally use elm for outgoing mail, which (even
with the enhancements I have added to it) cannot be persuaded to
generate mail in multipart/alternative format.  If I want to send MIME
attachments, I use mailto, which likewise cannot be persuaded to send
mail into multipart/alternative format.

I truly do not understand why some people send mail with alternative
text/plain and text/html formats.  Some people even send mail only in
text/html format, thus rendering it almost completely unreadable; had
I not recently publicly repented of unprofessional language, I would
be calling those people utterly moronic.  I do not understand why some
people think they need either hypertext or markup capabilities in
their outgoing mail.  If you want to send someone a URL, put the URL
in the body of your message, and you can even write "This is a URL" if
you believe that the recipient of your message cannot recognize a URL
when he sees one.  As for markup capabilites, I think you can manage
to communicate what you want to say without putting it in different
colors or fonts or typefaces or sizes.  If you truly cannot, then put
your message in a PDF file and send it over as a MIME attachment in
application/pdf format.

The second person said "Greylisting is harmless and only causes a very
small delay in mail delivery.  It needs no manual intervention".  I do
not know what is the source of this person's information, but it is
clearly a source into which he has deposited much too much confidence,
because his statement is untrue.  Greylisting does require manual
intervention.  I first have to notice that the recipient's MTA
returned a 400-level error code, and then I have to manually re-send
the mail.  If he has written an MTA that automatically re-sends mail
that is returned to him with 400-level SMTP errors, or if someone else
has written such an MTA for him, so that he does not have to manually
intervene when his outgoing messages are greylisted, then good for
him.  The MUAs that I use (elm and mailto) have been programmed to
hand outgoing mail to a Perl script that I wrote that does not (yet)
automatically re-send greylisted mail, and thus I have to re-send it
myself.

Okay, one funny story, but I will restrain myself from telling the
others.  As I said, I do my own mail filtering.  I am a freelance
instructor (and a very good one, parenthetically -- you can see a list
of all the classes I have taught, one-quarter of which I wrote myself,
at http://m5.chicago.il.us/classes.html).  I once failed to see --
because it was discarded by my mail-filtering software -- an important
e-mail with the title "URGENT: TRAINING SPECIALISTS NEEDED" and in
consequence I lost what would have been a lucrative training contract.
The reason why this message was discarded by my mail-filtering
software is that I used to get, with annoying frequency, e-mail
messages offering to sell me pills that promote marital happiness.  I
therefore wrote mail filtering rules that, inter alia, would discard,
unread, any incoming mail with a subject that contained the six-letter
brand name of one such pill.  The above-quoted subject ("URGENT:
TRAINING SPECIALISTS NEEDED") contained that six-letter brand name,
and therefore the message was discarded.  I later rewrote my
mail-filtering rule so that it would discard an incoming message only
if that six-letter brand name is surrounded by word separators.  I
eventually got it right, but I did not get it right on the first try.

Getting back to the post that occasioned this discussion in the first
place, I have noticed the complained-up phenomenon when the filesystem
containing home directories is out of space, because the graphical
login creates files and subdirectories underneath the user's home
directory, whereas the nongraphical login does not.  A followup
message on this mailing list stated that the filesystem is not out of
space.  I have also noticed the complained-up phenomenon on Linux
systems that enforce SELinux rules, if the shadow file was most
recently recreated on a system without SELinux, because the grapical
login requires /etc/shadow to have type shadow_t whereas the
nongraphical login does not.  This cannot be the case, however, on a
NetBSD system.  So I am curious to know the explanation of the
original poster's complained-of phenomenon, and I hope that the
original poster will tell us the explanation, when he discovers it.

                        Jay F. Shachter
                        6424 North Whipple Street
                        Chicago IL  60645-4111
                                +1 773 7613784   landline
                                +1 410 9964737   GoogleVoice
                                jay%m5.chicago.il.us@localhost
                                http://m5.chicago.il.us

                        "Quidquid latine dictum sit, altum videtur"