Fedora keeps sendmail — for now

Posted Aug 12, 2013 14:05 UTC (Mon) by mjg59 (subscriber, #23239)
In reply to: Fedora keeps sendmail — for now by dlang
Parent article: Fedora keeps sendmail — for now

Perform a stock Debian install, performing no additional configuration steps. Connect this computer to a standard residential internet connection which blocks outgoing port 25 (as the vast majority do). Are you able to send email to arbitrary email addresses?

Fedora keeps sendmail — for now

Posted Aug 12, 2013 20:55 UTC (Mon) by dlang (guest, #313) [Link] (9 responses)

If you set the Debian install to use your ISPs mail server as it's smarthost, then yes, you probably can send mail to arbitrary addresses on the Internet (at least, if you send them from an e-mail address your ISP assigned to you)

Fedora keeps sendmail — for now

Posted Aug 12, 2013 20:59 UTC (Mon) by mjg59 (subscriber, #23239) [Link] (8 responses)

That would be an additional configuration step, so it doesn't answer my question.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:10 UTC (Mon) by dlang (guest, #313) [Link] (7 responses)

that configuration is done during the install, as others have pointed out.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:25 UTC (Mon) by mjg59 (subscriber, #23239) [Link] (6 responses)

Having just performed a Debian install, I can assure you that it isn't.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:45 UTC (Mon) by dlang (guest, #313) [Link] (1 responses)

since you are saying that this has to work without any configuration step, I'm surious as to what MUA you are using that works without any configuration.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:48 UTC (Mon) by mjg59 (subscriber, #23239) [Link]

Sigh. No, that's not what I'm saying. What I'm saying is that you can't depend on there being a system-wide MTA that can deliver to the outside world, and as such any software that's expected to run on arbitrary machines cannot rely on the sendmail command doing anything useful.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:48 UTC (Mon) by cas (guest, #52554) [Link] (3 responses)

if that's the case, it would only be because people like you have succeeded in having an MTA (the default used to be exim) excluded from the default install. and then to add insult to injury you triumphantly claim "look, it doesn't work, i told you so!".

if that's the case then i wouldn't have noticed because i always install postfix instead of exim. and i can assure you that when you do install an MTA in debian, it does indeed offer to create a basic configuration for you with about 4 or 5 options for you to choose from - one of which is "send all mail through a smarthost"

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:56 UTC (Mon) by mjg59 (subscriber, #23239) [Link]

Exim's still installed by default, it's just not configured to do remote delivery.

Fedora keeps sendmail — for now

Posted Aug 13, 2013 8:48 UTC (Tue) by anselm (subscriber, #2796) [Link] (1 responses)

But that still leaves you out in the cold if your ISP wants you to submit mail to port 587 with TLS and SMTP AUTH. You will need to configure that manually – in a manner that depends on your specific MTA – after the installation.

The fact remains that ISP mail setups are diverse enough that any method of getting mail off the local machine – via a local MTA or an MUA – requires configuration. Instead of debating whether a system should come with a full-blown MTA like Sendmail by default, it would arguably be more productive to come up with a standardised scheme of representing ISP mail setups such that a user could be asked »What is your e-mail address (and possibly submission password)?« and the system could figure out automatically, for a reasonable majority of common ISPs, how to configure the local MTA or MUA of the user's choice to actually send mail using whatever access method that ISP supports, including goodies like encryption if it is available.

Fedora keeps sendmail — for now

Posted Aug 13, 2013 10:02 UTC (Tue) by dlang (guest, #313) [Link]

i don't think that you would find anyone who is opposed to such a tool being created.

Just the work of identifying the different types of access, enumerating them, and maintaining a list of per-ISP configs would be of immense value.

then configuring MTA or MUA software from that data would be much easier.

and by the way, as long as the actual work of configuring the MTA/MUA was modular and scriptable, this would also fit into the "Unix way" quite nicely :-)

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:33 UTC (Mon) by cas (guest, #52554) [Link] (5 responses)

oh no! the sky is falling! an ISP that blocks smtp makes sending mail difficult. and it's all the MTA's fault.

this is even more contrived than the last example someone posted.

it's also a good example of why a local MTA is useful...you've got a lot more tricks up your sleeve to work around blockage with an MTA than you have with an MUA.

next up, "try to send mail from a laptop with a dead battery, during a power outage with no wifi or wired network available. you can't, see! and it's all the stupid MTA's fault".

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:40 UTC (Mon) by mjg59 (subscriber, #23239) [Link] (4 responses)

The vast majority of residential ISPs block outgoing port 25 traffic, and those that don't will probably still be unable to deliver mail because their IP blocks will be in SORBS. This isn't a contrived example. This is the common case.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 21:53 UTC (Mon) by cas (guest, #52554) [Link] (3 responses)

and the user will have just as much (or more) difficulty configuring an MUA to work around the block.

stop pretending that this is the MTA's fault.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 22:00 UTC (Mon) by mjg59 (subscriber, #23239) [Link] (2 responses)

This discussion started with you claiming "the whole point of having /usr/sbin/sendmail on a system (whether that's provided by sendmail, exim, postfix, ssmtpd or anything else) is that other programs don't have to know how to route or deliver mail, they just pipe it to /usr/sbin/sendmail." Perhaps that's how it should be - there are clear benefits to things being configured in one place, and there are clear benefits to not reimplementing SMTP dozens of times. But, unfortunately, that's not how it is. If you want to send mail, you can't depend on the sendmail command.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 22:37 UTC (Mon) by cas (guest, #52554) [Link] (1 responses)

and as i said several times previously, you can't depend on the MUA being configured or working either.

just saying "it's too hard" and giving up is not a solution.

to configure either an MUA or an MTA there's a certain minimum amount of knowledge and understanding (or at least facts, like the smarthost name or IP address) required.

the same questions will be asked of the user, and a useful answer required - whether that's asked in a dialog/whiptail popup, a GUI dialog, or a plain tty style.

also, some here seem to think that only a GUI or ncurses app is an MUA. or that only automated scripts, cron job need to send mail via command-line interface.

/usr/sbin/sendmail *IS* an MUA. as is /usr/bin/mail. I can use them to send useful information to any email address....and I can do it reliably and conveniently, with consistent and documented command-line options.

grep foobar /var/log/something.log | sendmail me@somewhere.example.com

that's using an MUA. if i want to get fancy, i can use other command-line tools to compress the log extract and send it as a properly formatted mime-attachment.

Fedora keeps sendmail — for now

Posted Aug 12, 2013 22:46 UTC (Mon) by mjg59 (subscriber, #23239) [Link]

"and as i said several times previously, you can't depend on the MUA being configured or working either."

Yup. As a result, email's a poor default for reporting things, and so josh is trying to fix the fact that there are still things in Debian that default to logging via email. As you've demonstrated, it's easy to bridge from syslog to email if you know that your local configuration supports that.