Changes/NoDefaultSendmail

No More Sendmail

Summary

Change "comps" to no longer install an MTA by default, more specifically let's remove sendmail from the default install!

Owner

• Name: Lennart Poettering
• Email: lennart at poettering net
• Release notes owner:

Current status

• Targeted release: Fedora 20
• Last updated: 2013-07-08
• Tracker bug: <will be assigned by the Wrangler>

Detailed Description

Let's change the default install to no longer install an MTA by default, let's remove sendmail from the "comps" default.

On today's Internet most SMTP hosts do not accept mail unrestricted anyway, hence the default configuration of sendmail is seldom useful. Something that doesn't work without manual configuration should not be in the default install however.

The MUAs we ship (especially those we install by default) do not deliver to a local MTA anyway but rather include an SMTP client.

On top of that, sendmail has always been a quite surprising choice for an MTA, as most administrators tend to prefer mail systems such as Postfix or Exim these days, and Sendmail appears to be a quite arcane choice to most.

Administrators should install the MTA of their choice after installation (or via kickstart) however sendmail should not be the default anymore.

Many other distributions do not install an MTA by default anymore, and so should we. Running systess without MTA is already widely tested.

The various tools (such as cron) which previously required a local MTA for operation have been updated already to deliver their job output to syslog rather than sendmail, which is a good default.

Benefit to Fedora

Our default install will need less footprint on disk and at runtime. We'll boot a bit faster. Our attack surface is slightly smaller, as we'll have one less daemon running by default that communicates via IP.

Scope

Simply remove "sendmail" from all default instal groups in "comps".

Packages which strictly require a MTA to run might need updating to gain dependencies on some kind of MTA (but they needed that before too, so this is mostly just bugfixing that's useful anyway). If any of the packages in the default install is one of those, we need to look at it in detail, and find a solution. However, currently no package of the default install is requiring an MTA.

• Proposal owners:

Commit a change to "comps" to remove "sendmail" from it.

• Other developers: not much, just test F20 regularly.

• Release engineering: nothing really.

• Policies and guidelines: nothing really. Maybe the guidelines should clarify that /usr/bin/sendmail doesn't exist on many systems, but that was already the case before so little changes.

Upgrade/compatibility impact

Old installs will continue to have sendmail installed, nothing changes for them.

How To Test

Just make sure that everything works correctly, and that cronjob output ends up in the system logs.

User Experience

Few people should notice. Adminsitrators might need to install an MTA first before they can configure it.

Dependencies

Nothing really.

Contingency Plan

• Contingency mechanism: Readd "sendmail" to comps.
• Contingency deadline: beta release
• Blocks release? not really, it's trivial to revert and has no dependency in other packages.

Documentation

Nothing really. This is a relatively simple change.

Release Notes

Maybe something like this should be added to the release notes:

"Note that F20 does not install a Mail Transfer Agent by default anymore. If the administrator needs local mail delivery or wants to set up a mail server we recommend installing an MTA such as Postfix, Sendmail or exim with a command like like the following:

$ yum install postfix"