[lug] mail server preference

Sean Reifschneider jafo at tummy.com
Fri Dec 8 15:53:45 MST 2006

On Fri, Dec 08, 2006 at 01:05:43PM -0700, Ken MacFerrin wrote:
>> Because of the alternatives system, it's not a problem at all.
>Yup.. and most MTAs provide a replacement "sendmail" binary for
>backwards compatibility as well.

That's what the alternatives system deals with:

   guin:~$ rpm -q --provides postfix
   config(postfix) = 2:2.3.3-2
   postfix = 2:2.3.3-2

So, the postfix package provides /usr/sbin/sendmail.  But, when you check

   guin:~$ ls -ld /usr/sbin/sendmail
   lrwxrwxrwx 1 root root 21 Mar 26  2006 /usr/sbin/sendmail -> /etc/alternatives/mta

It's actually a link to /etc/alternatives:

   guin:~$ ls -l /etc/alternatives/mta
   lrwxrwxrwx 1 root root 26 Nov 19 22:03 /etc/alternatives/mta -> /usr/sbin/sendmail.postfix

That's why you can install postfix and then remove sendmail, without them
conflicting by being installed at the same time.

 Come see the violence inherent in the system!
 Help!  Help!  I'm being repressed!  -- Monty Python and the Holy Grail
Sean Reifschneider, Member of Technical Staff <jafo at tummy.com>
tummy.com, ltd. - Linux Consulting since 1995: Ask me about High Availability

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