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Re: switching from exim to postfix

On Tue, May 01, 2012 at 12:48:10AM -0400, Chris Knadle wrote:
> I think it would be useful to describe what issue(s) there are concerning 
> 8BITMIME and why this is important.  I've found some information [1] about 
> this, but it isn't clear what problems are actially *caused* by the lack of 
> 8BITMIME support by default in Exim.  Is it just slow sending of outbound 
> attachments?

It's both extra traffic (not that much if western encodings) and extra
cpu work. In lesser annoyance, it means that you no longer can read
mailbox files with non-mime capable readers (for example less) with ease,
as there will be qp encodings here and there. People who only use english
only hit the issue when having lines longer than 76 characters.

Basicly that the qmail author is suggesting is violating the rfc by
announcing 8bitmime sopport but never doing any conversions if you bump
into a server that doesn't support 8bitmime. This is the same as the
exim's accept_8bitmime option.

In the real world, violating the rfc is a non-issue, as most likely the
only non-8bitmime compliant servers your server encouters are qmail and exim4,
both which have no problems with 8bit mails itself.

Honesstly. my grievance is really just having to convert things to 7bit.. still!

> The quoted 2010 survey [2] showed Exim was the most popular MTA (which I found 
> surprising), deployment of Exim growing just slightly faster than Postfix, and 
> everything else falling in popularity. 

I think it is because other distro's have mostly stopped shipping
anything that listens on port 25 by default.

> I don't know how one would verify (or dispute) the claim that Debian was the
> main source of Exim installs

Indeed that is not verifiable from the given report. However, they list
the most common exim version being 4.69 which is same as what was in
lenny at that time.

> > So yes, switching to postfix by default  would reduce the workload of email
> > servers around the globe (no need to burn cpu cycles and thus co2 to
> > convert emails to quoted-printable).
> The statistics quoted showed that Exim was most popular, so wouldn't switching 
> to Postfix by default actually be more CPU costly than the reverse?  :-/  [I'm 
> not saying you're wrong, just that I don't see the logic in the argument.]

The less there are MTA's out there not announcing 8bitmime, the less
conversions there will be (eventually). While the exim->exim deliveries
are not generating conversions (unless the MUA does it), exim is still
only at 34% of mx, not 34% of the traffic.

> I've likewise often wondered if a low-resource MTA like DMA or ssmtp could be 
> the default MTA for Desktop installs (and I've occasionally tried them), but 
> as has been discussed there seem to be some issues with the idea.  In my case 
> for Desktops I want the local MTA to be able to handle sending local outbound 
> mail to a server via port 587 over TLS with authentication, to retry sending 
> at increasing time intervals, using a "queue runner" but without a daemon 
> listening, and to notify the sender on a permanent failure.  Thusfar I've only 
> been able to find all of that in a full-fledged MTA.

Indeed, switching to a lightweight mta like dma as default makes probably more
sense than switching by default postfix. I tried ssmpt and it didn't
work for me.. Would dma do TLS auth and queque fine?


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