[CentOS] How to configure sendmail

Mon Dec 3 02:49:05 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Sun, Dec 2, 2012 at 8:22 PM, Phil Dobbin <bukowskiscat at gmail.com> wrote:
>>> If you don't like things that use traditional unix tools for the
>>> purposes they were designed, why are you interested in using linux at
>>> all?  From a user perspective making a few changes to sendmail.mc and
>>> restarting the sendmail service is quite easy.
>> I once knew my way around the 'rules' in the .cf file.     thats truly
>> some evil arcane magic in there.
> Whilst bowing in due deference to people who've been using *nix/Linux
> since it required a piece of string, two tin cans & coven in order to
> achieve results, I was under the impression that nowadays, unless you
> actually need some functionality that sendmail has & nothing else
> possesses, the received wisdom for novices when setting up all things
> mail was using postfix in its place.

Well, there was a time when a lot of stuff was broken or badly
designed in sendmail, and starting from scratch might have made sense,
but meanwhile sendmail has been fixed and is now probably one of the
most carefully audited piece of code around.    And while you _can_
write original sendmail .cf code to make it do things that no one ever
thought of before, almost no one needs to do that anymore.   Instead,
you start with the nearly-working sendmail.mc that RH/CentOS includes
and change the few parts you need for your local setup.  These changes
are just to invoke already written macros that are already in place
for pretty much everything you might want a mailer to do.   Or you use
the milter interface to add new program steps like spam filtering
(postfix has that too, now).

> All documentation I've ever read regarding postfix starts with
> declaration that postfix is a replacement for sendmail, it's widely
> recommended as a replacement & having used postfix after attempting to
> use sendmail, I can see why (I too have Eric Allman's big book & also
> have read anecdotes written by Brian Kernighan on its origins & very
> interesting & enlightening they are too). But surely, the effort
> required to be competent enough to use it properly far outweighs the
> benefits just for the casual user.

Correct - unless you have very unusual needs, you shouldn't tackle
direct changes to sendmail.cf.   But a casual user is going to just
cut and paste a few lines from a reference, tutorial, or email answer
into their sendmail.mc or postfix configs without understanding the
full scope of their capabilities anyway.  And at that level there
isn't a big difference in what it takes to make them work - especially
given that the distro comes with pretty close to working configs
already.   And once they work, in most cases you don't need to which
is running.

    Les Mikesell
     lesmikesell at gmail.com