Change smtps to submissions in master.cf

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Change smtps to submissions in master.cf

Anton Rieger
Hi there,

currently the IANA assigned 465/tcp to urd and submissions and dropped support for smtps
thus I suggest to change smtps to submissions in the default master.cf.

I checked Linux Distributions I have access to:
- Arch Linux uses submissions
- Scientific Linux 7.6 uses smtps (alias)
- Ubuntu 16.04.6, 18.04.3 uses smtps,ssmtp (alias)
- Ubuntu 19.04 uses submissions and ssmtp,smtps (alias)

Greetings
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Re: Change smtps to submissions in master.cf

Matus UHLAR - fantomas
On 07.09.19 17:45, Anton Rieger wrote:
>currently the IANA assigned 465/tcp to urd and submissions and dropped
>support for smtps thus I suggest to change smtps to submissions in the
>default master.cf.

The names are related to service name in /etc/services, it's not that easy
to rename them there

>I checked Linux Distributions I have access to:
>- Arch Linux uses submissions
>- Scientific Linux 7.6 uses smtps (alias)
>- Ubuntu 16.04.6, 18.04.3 uses smtps,ssmtp (alias)
>- Ubuntu 19.04 uses submissions and ssmtp,smtps (alias)

--
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Warning: I wish NOT to receive e-mail advertising to this address.
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Re: Change smtps to submissions in master.cf

Viktor Dukhovni
In reply to this post by Anton Rieger
> On Sep 7, 2019, at 11:45 AM, Anton Rieger <[hidden email]> wrote:
>
> IANA assigned 465/tcp to urd and submissions and dropped support for
> smtps thus I suggest to change smtps to submissions in the default
> master.cf.

The first column in master.cf "inet" entries takes the form:

        [<hostname-or-address>:]<service-name-or-number>

(where [...] means that "..." is optional).  When a host and/or
a service name is used, it has to resolve an IP address or port
number via a suitable name resolution mechanism.

Since master.cf service names do not appear "on the wire", but
are used only locally, as lookup keys into local databases, stability
and backward compatibility may be more important than conformance with
IANA registrations.

In any case, the upstream master.cf entry in question is commented out,
and OS distributions can change it to match whatever they put into
/etc/services.  So I don't think it necessary to make the proposed
change quite yet.

Tweaking the stock master.cf to match /etc/services while optionally
enabling "TLS wrapper mode" submission is up to distributions and
users who build their own master.cf files by hand.

Postfix supports a broad range of operating systems, from rather
dated "stable" releases to the latest bleeding-edge built from
upstream sources.  So sometimes it makes sense to target a
comparatively dated moving target "reference platform".

--
        Viktor.

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Re: Change smtps to submissions in master.cf

Anton Rieger
In reply to this post by Matus UHLAR - fantomas
>The names are related to service name in /etc/services, it's not that easy
>to rename them there
It's not about renaming them in /etc/services, but to remove the default template in
master.cf.

The new Releases of Linux Distributions and *BSDs out there will eventually ship the new
IANA port numbers with /etc/services.
Not all of them are so nice to include legacy aliases.
If postfix changes the default template to submissions newer releases of Linux
Distributions and *BSDs are supported OOTB.
Package maintainers can still apply a patch to change it back to smtps for systems not
yet supporting submissions in /etc/services.

This change is also supported by RFC 8314 [1] and IANA.

[1] https://tools.ietf.org/html/rfc8314
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Re: Change smtps to submissions in master.cf

Anton Rieger
In reply to this post by Viktor Dukhovni
>The first column in master.cf "inet" entries takes the form:
>
> [<hostname-or-address>:]<service-name-or-number>
>
>(where [...] means that "..." is optional).  When a host and/or
>a service name is used, it has to resolve an IP address or port
>number via a suitable name resolution mechanism.
I'm aware of that and changed it on my system to submissions as smtps
ist not in /etc/services.

>Since master.cf service names do not appear "on the wire", but
>are used only locally, as lookup keys into local databases, stability
>and backward compatibility may be more important than conformance with
>IANA registrations.
This would only trigger new updates.
Alternatives to avoid this issues are:
1) Support both variants in the template
2) It's commented out anyway
3) These "stable/old" releases tend to change a lot from the vanilla releases anyway

>In any case, the upstream master.cf entry in question is commented out,
>and OS distributions can change it to match whatever they put into
>/etc/services.  So I don't think it necessary to make the proposed
>change quite yet.
It was just a suggestion and in my release also commented out.
Just thought as new users to setup a postfix server might find it easier to directly find
submissions rather than smtps and use this.

>Tweaking the stock master.cf to match /etc/services while optionally
>enabling "TLS wrapper mode" submission is up to distributions and
>users who build their own master.cf files by hand.
Or they could tweak it to use smtps.
It can be turned around as one wishes.
As it's default comment out, I don't see a big issue to make it future proof.

>Postfix supports a broad range of operating systems, from rather
>dated "stable" releases to the latest bleeding-edge built from
>upstream sources.  So sometimes it makes sense to target a
>comparatively dated moving target "reference platform".
And these systems to change a lot from the vanilla source anyway.


Anton
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Re: Change smtps to submissions in master.cf

Peter Ajamian
In reply to this post by Anton Rieger
On 8/09/19 3:45 AM, Anton Rieger wrote:
> Hi there,
>
> currently the IANA assigned 465/tcp to urd and submissions and dropped
> support for smtps thus I suggest to change smtps to submissions in the
> default master.cf.

Do this and ...

> I checked Linux Distributions I have access to:
> - Arch Linux uses submissions

You fix things in this distro.

> - Scientific Linux 7.6 uses smtps (alias)
> - Ubuntu 16.04.6, 18.04.3 uses smtps,ssmtp (alias)
> - Ubuntu 19.04 uses submissions and ssmtp,smtps (alias)

But you break things in these ones.

I'm sure eventually we'll be making this change, but let's wait until it
fixes more distros than it breaks.


Peter
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Re: Change smtps to submissions in master.cf

Anton Rieger
>>- Scientific Linux 7.6 uses smtps (alias)
>>- Ubuntu 16.04.6, 18.04.3 uses smtps,ssmtp (alias)
>>- Ubuntu 19.04 uses submissions and ssmtp,smtps (alias)
>
>But you break things in these ones.
Scientific Linux is discontinued
Ubuntu changes the default master.cf and main.cf anyway through their dpkg-reconfigure
script.

Also the default is commented out. No breaking would occur.

>
>I'm sure eventually we'll be making this change, but let's wait until
>it fixes more distros than it breaks.
Sure thing.
The next Ubuntu LTS release should have submissions as default port mapping.

Debian 9 currently also doesn't support submissions mapping.

Somebody using RHEL, CentOS or Fedora would be nice checking.

Anton
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Re: Change smtps to submissions in master.cf

Robert Wolfe
Using CentOS here. Will check and see what the setting is here.

On Sep 13, 2019, at 5:04 PM, Anton Rieger <[hidden email]> wrote:
- Scientific Linux 7.6 uses smtps (alias)
- Ubuntu 16.04.6, 18.04.3 uses smtps,ssmtp (alias)
- Ubuntu 19.04 uses submissions and ssmtp,smtps (alias)

But you break things in these ones.
Scientific Linux is discontinued
Ubuntu changes the default master.cf and main.cf anyway through their dpkg-reconfigure
script.

Also the default is commented out. No breaking would occur.


I'm sure eventually we'll be making this change, but let's wait until
it fixes more distros than it breaks.
Sure thing.
The next Ubuntu LTS release should have submissions as default port mapping.

Debian 9 currently also doesn't support submissions mapping.

Somebody using RHEL, CentOS or Fedora would be nice checking.

Anton