why does topal depend on postfix?

Asked by AlexCharis on 2012-01-31

i've set up a gpg key and i regularly use alpine to read and send emails.
i would like to encrypt, decrypt, sign and verify emails in alpine using gpg.
topal advertises itself as the necessary glue to make this happen.

sudo apt-get -s install topal
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  gnat-4.4-base libgnat-4.4 postfix procmail
Suggested packages:
  postfix-mysql postfix-pgsql postfix-ldap postfix-pcre sasl2-bin dovecot-common resolvconf postfix-cdb metamail
The following NEW packages will be installed:
  gnat-4.4-base libgnat-4.4 postfix procmail topal
0 upgraded, 5 newly installed, 0 to remove and 9 not upgraded.
Inst gnat-4.4-base (4.4.3-1ubuntu1 Ubuntu:10.04/lucid)
Inst libgnat-4.4 (4.4.3-1ubuntu1 Ubuntu:10.04/lucid)
Inst postfix (2.8.5-2~build0.10.04 Ubuntu:10.04/lucid-backports)
Inst procmail (3.22-18ubuntu1 Ubuntu:10.04/lucid)
Inst topal (72-1 Ubuntu:10.04/lucid)
Conf gnat-4.4-base (4.4.3-1ubuntu1 Ubuntu:10.04/lucid)
Conf libgnat-4.4 (4.4.3-1ubuntu1 Ubuntu:10.04/lucid)
Conf postfix (2.8.5-2~build0.10.04 Ubuntu:10.04/lucid-backports)
Conf procmail (3.22-18ubuntu1 Ubuntu:10.04/lucid)
Conf topal (72-1 Ubuntu:10.04/lucid)

it depends on postfix, among other things.

postfix is a mail transfer agent. i do not expect the installation of an MTA to be necessary to use my chosen MUA.

i'm trying to do:
"Include as much detail as possible: what you’re trying to achieve, what steps you take, what happens, and what you think should happen instead."

and i have told you what i do not expect to happen.

what i do expect to happen is:
i install and configure topal, telling it about a default key.
then, i can reasonably expect to do some configuration in alpine.
then, i reasonably expect to be able to decrypt, encrypt, sign and verify emails inside alpine with gpg.


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Ubuntu topal Edit question
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Solved by:
Alessandro Menti
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Best Alessandro Menti (elgaton) said :

Hello Alex,
I have inspected the package dependencies using <http://packages.ubuntu.com/oneiric/topal>.

There is no "required" dependency between topal and postfix, but there is a "recommended" one between topal->procmail->default-mta/mail-transport-agent (the latter packages are meta-packages provided by postfix, among others).

It seems that apt-get is configured on your box to pull in not only essential dependencies, but recommended packages as well, and that's why it asks you to install postfix.

To prevent apt-get from installing suggested and recommended packages, open a Terminal, type "sudo nano /etc/apt/apt.conf" and add the following lines (or change them if similar ones are present):
APT::Install-Recommends "false";
APT::Install-Suggests "false";
then exit with Ctrl+X and type "y" and Enter to save.

You may also prevent apt-get from installing non-essential packages for one time only by passing it the "--no-install-recommends" parameter, like this:
sudo apt-get install --no-install-recommends <package>

Let me know if that solved your problem.

Revision history for this message
AlexCharis (acharis) said :

Thanks Alessandro Menti, that solved my question.