Mailing List Archive

VRFY and EXPN issues (Was: two qmail questions)
At 03:17 PM 2/18/97 -0800, you wrote:
>Vladimir Gabrielescu <vgabriel@lochaber.rutgers.edu> writes:
>
>In my opinion, EXPN and VRFY are excess interactions that don't
>contribute to the overriding goal of an MTA: Transporting E-mail.
>Any information about whether a host can deliver to an address can
>be found in the response to the smtp "RCPT TO:" command. EXPN and
>VRFY are unnecessary to the actual transport of mail, so a mail
>transport agent shouldn't be required to support them.

Nevertheless, there are, I have found, times where this extra feature
is *very* useful from an administrative point of view. Our company
maintains aliases for our users in the form fmlast@switch.com, which I
now happen to maintain. When I picked this up, many of the alias where
using only initials, and pointing at machines that I didn't have access
to (the function changed groups, also). Some of these machines didn't
implement finger, but almost all of them implemented VRFY. So, I was
able to write a script which processed the Sendmail alias file they
were in, and find out who had what alias for 95% of the names (around
400) that existed at that time. This saved me a *lot* of time on the
phone, so that I could create aliases in the full format.

Now, on a monthly basis, I run this sort of script to identify aliases
that need changed, as of course with the dynamic nature of our workplace,
users are sometimes moved to different machines, and the people involved
forget they need to tell me about it :) I should certainly not be able
to support the user email community as well if VRFY was not implemented
on most of our internal machines. I believe we were asked to give
real-life examples of difficulties that one might have with QMAIL; well,
this is such an example. Maybe not a show stopper, but none the less a
difficulty.
-------------------------
John C. Ring, Jr.
jcring@switch.com
Network Specialist
Union Switch & Signal Inc.
Re: VRFY and EXPN issues (Was: two qmail questions) [ In reply to ]
> Nevertheless, there are, I have found, times where [ VRFY ]
> is *very* useful from an administrative point of view.

Qmail's design means it will never support VRFY: qmail-smtpd doesn't
even know whether an address is local or remote.

Here's a fingerd I just whipped up which you could run on a qmail
machine in order to get information about its local mailboxes, if you're
not using qmail-users(5). (Support for qmail-users is left as an
exercise for the reader. :-)

#! /usr/bin/perl
$ENV{PATH}='/var/qmail/bin';
($user = <STDIN>) =~ s/\r\n$//;
@info = split(/\0/, `qmail-getpw $user`);
print `qmail-alias -n "$info[0]" "$info[3]" "$user" "$info[4]" "$info[5]" LOCALHOST ""`;
exit 0;

Tim.
Re: VRFY and EXPN issues (Was: two qmail questions) [ In reply to ]
Excerpts from internet.computing.djb-qmailbeta: 19-Feb-97 VRFY and EXPN
issues (Was: .. by "John C. Ring, Jr."@swit
> users are sometimes moved to different machines, and the people involved
> forget they need to tell me about it :) I should certainly not be able
> to support the user email community as well if VRFY was not implemented
> on most of our internal machines. I believe we were asked to give
> real-life examples of difficulties that one might have with QMAIL; well,
> this is such an example. Maybe not a show stopper, but none the less a
> difficulty.

Another real-life example: as the Net Admin for ML.ORG free domain name
services, we often get people checking email addresses and stuff at our
site, which now runs Qmail. More and more are complaining that they can't
run VRFY/EXPN. It makes me laugh somewhat when other sysadmins go "Your
Mail Program is decidedly unfriendly" when Qmail tries to be so clear to
users.. :)

Aveek Datta _ _ _ _ Email: aveek@andrew.cmu.edu
_ __ ___ _ _ ___| (_) |_| |_ |W| HomePage: datta.ml.org
_| ' \/ _ \ ' \/ _ \ | | _| ' \ _ |E| FreeDNS: www.ml.org
(_)_|_|_\___/_||_\___/_|_|\__|_||_(_) |B| Work: www.itc.cmu.edu
Re: VRFY and EXPN issues (Was: two qmail questions) [ In reply to ]
> Excerpts from internet.computing.djb-qmailbeta: 19-Feb-97 VRFY and EXPN
> issues (Was: .. by "John C. Ring, Jr."@swit
> > users are sometimes moved to different machines, and the people involved
> > forget they need to tell me about it :) I should certainly not be able
> > to support the user email community as well if VRFY was not implemented
> > on most of our internal machines. I believe we were asked to give
> > real-life examples of difficulties that one might have with QMAIL; well,
> > this is such an example. Maybe not a show stopper, but none the less a
> > difficulty.
>
> Another real-life example: as the Net Admin for ML.ORG free domain name
> services, we often get people checking email addresses and stuff at our
> site, which now runs Qmail. More and more are complaining that they can't
> run VRFY/EXPN. It makes me laugh somewhat when other sysadmins go "Your
> Mail Program is decidedly unfriendly" when Qmail tries to be so clear to
> users.. :)

Seems like a legitimate concern, but since my understanding is that the design
of qmail would make it hard to implement, it might be better to throw together
a finger server that would do this and then modify the error that is generated
when someone tries to do an EXPN to suggest using finger instead.

Chris

--
Chris Garrigues O- cwg@DeepEddy.Com
Deep Eddy Internet Consulting +1 512 432 4046
609 Deep Eddy Avenue
Austin, TX 78703-4513 http://www.DeepEddy.Com/~cwg/