Re: Questions regarding lsb-invalid-mta

On 06/23/2013 03:03 PM, Aaron Sowry wrote:
> Okay. So, Debian considers an MTA to consist of both a server and client
> component. This seems like a sensible enough definition.

Sort of.  Strictly speaking, a "mail transport agent" is an agent which 
transports mail.  So as long as mail coming into the system gets 
transported, whether the MTA is a full-featured system like Sendmail or 
something a lot simpler.

At least, that's the Debian perspective (and one which I agree with).

I'm not saying that these "not-full-featured" MTAs are as limp as 
lsb-invalid-mta, either; ssmtp, for example, just takes mail submitted 
via /usr/sbin/sendmail and forwards it to a relay that accepts mail on 
port 25.  I think that's a very valid MTA implementation, and 
appropriate for a number of circumstances.  I use it on most of my home 
machines, with one server as the central relay running Postfix.

> If we want to
> provide /usr/sbin/sendmail without installing an entire MTA then, I
> guess we have two options:
>
> 1) Install the entire MTA, but leave the server component unconfigured
> (assuming this is even possible). Enabling the server component later
> could be done using dpkg-reconfigure.

This is possible.  The exim4-daemon-light package, for example, takes 
heroic steps to do the right thing in as many situations as possible 
without any end-user configuration, which is why it's the default.

> 2) Make a new package available which provides only /usr/sbin/sendmail,
> but not "mail-transport-agent" (i.e. installs no server). In this case,
> I guess all packages providing mail-transport-agent would need to
> replace this package.

I think every package that provides /usr/sbin/sendmail on Debian also 
provides "mail-transport-agent", even the aforementioned options like 
ssmtp which are little more than relays to another host.

Some of the packages that look stripped down are actually just the MTA 
component of bigger things; Citadel, for example, is a complete 
groupware suite, including mail, calendaring, contacts, forums/bulletin 
boards, etc.