[CentOS] Setting up postfix under CentOS-6

[Timothy Murphy]

Carl T. Miller wrote:

>> I'll try following the instructions in that document,
>> as I have had no luck with the documents on www.postfix.org .
> 
> I have switched over from sendmail to postfix, and the
> most difficult part was learning how simple it is to
> configure postfix.

Why should it be difficult to learn that,
unless the documentation is misleading?
(It is.)

> I'd be surprised if anything in that document is not
> right.  If you find anything or you need assistance,
> the list is here.

I didn't find anything wrong in the document in question
(http://wiki.centos.org/HowTos/postfix),
except that a couple of packages mentioned
(ystem-change-mail*) don't seem to exist in CentOS-6.

However, if my experience is anything to go by,
it missed out two essential points.

Firstly, after following the instructions meticulously,
I found that I could not send out mail
because (according to /var/log/maillog)
the From address was tim at localhost.localdomain ,
and this was rejected by the recipient host
or rather his ISP.
-------------------------------
<tim at localhost.localdomain>  MAIL FROM domain does not exist 
  (in reply to MAIL FROM command)
-------------------------------
I cured this by adding
  tim tim at gayleard.eu
to /etc/hosts .
I don't know if this is the best way to go about it?

After correcting this, I found my email was still rejected,
with the message "Blacklisted by Spamhaus"!
I read in <http://www.spamhaus.org/pbl/query/PBL814205>
that 'the reason is simply that you need to turn on "SMTP Authentication"'

Googling for "centos postfix authentication" took me on a long
and not very interesting journey.
I was amazed how many apparently widely differing solutions were suggested.
In the end I found the simplest solution in 
<http://www.cyberciti.biz/faq/postfix-smtp-authentication-for-mail-servers/>
which describes the postfix equivalent of sendmail's SMART_HOST.
(A lot more complicated than the one line in sendmail.mc .)

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland