Sorry to come back only now. I upgraded to 12.2
Well, I was stumped because of an error message which, after all, seems not to be pertinent to my problem (or is it?). I changed the name in smartd.conf and main.cf to (root@)whatever.local. This is the contents of the mail I get:
From email@example.com Fri Oct 19 18:04:40 2012
Date: Fri, 19 Oct 2012 18:04:40 +0200
Subject: SMART error (EmailTest) detected on host: netbook
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: firstname.lastname@example.org (root)
This email was generated by the smartd daemon running on:
host name: netbook
DNS domain: [Unknown]
The following warning/error was logged by the smartd daemon:
TEST EMAIL from smartd for device: /dev/sda [SAT]
For details see host's SYSLOG.
Is it a smart pseudo-error then to generate the mail or is it a postfix error? I think and hope the first, but I am not sure.