[lug] mail server preference

[Sean Reifschneider]

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
   /usr/bin/mailq  
   /usr/bin/newaliases  
   /usr/bin/rmail  
   /usr/sbin/sendmail  
   MTA  
   config(postfix) = 2:2.3.3-2
   smtpd  
   smtpdaemon  
   postfix = 2:2.3.3-2
   guin:~$ 

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

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

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
   guin:~$ 

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

Sean
-- 
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Sean Reifschneider, Member of Technical Staff <jafo at tummy.com>
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