Making Postfix activated over Sendmail, how? How to test email sending?

Hello!   everyone,

I have a brand new Web Server (, and it is collocated to an ISP (Internet Service Provider) near my office.   The IPS suggested me to use Postfix rather than Sendmail for Mail Transport Agency.   Right now, I have a temporarily setup that the ISP's other host machine play the role of MTA (Mail Transport Agent) as the name of "".   It was fine for a little while, but I have a desire to send and receive emails directly from the own Web Server machine ( -  

Then, I started my challenge to configure Postfix Mail server.   I learned that,
is the configuration file about most control over Postfix.   Then I learned that,
   /usr/sbin/postfix start
makes activate Postfix deamon.   Now, at least on that Server machine, Postfix deamon is running.   As shown below.  

The first problem is there is a competetion between Sendmail and Postfix in the machine, and I don't know how to fix only to the Postfix as MTA.

The second problem is that I don't know how to test email-sending and receiving while another machine is currently assigned the role of "".   At least I want to send email out from ( -, but I do not know any way to test it.

I think I have to go through many challenges, but please advice me piece by piece of knowledge I have to learn and know, to fulfill my goal.   Thank you !   I attach my DNS report status, so that you, experts, may suggest the health of my domain's setting.

Here is a little bit of /var/log/maillog,

Jul  8 17:17:13 biwa postfix/postfix-script: stopping the Postfix mail system
Jul  8 17:17:13 biwa postfix/master[5792]: terminating on signal 15
Jul  8 17:17:19 biwa postfix/postfix-script: starting the Postfix mail system
Jul  8 17:17:19 biwa postfix/master[6338]: daemon started -- version 2.0.11


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Cyclops3590Connect With a Mentor Commented:
first of all postfix was meant to actually be easily migratable from sendmail.  This causes problems when both are installed.  Each have a sendmail binary they use (each different) so if sendmail was installed first, then postfix.  Postfix tries to use Sendmail's sendmail and screws up.  This can only be fixed (at least in my experience as of yet) to uninstall both Sendmail and Postfix, then install Postfix.  Unless something specifically references Sendmail for some reason there shouldn't be an issues in doing this

When the postfix daemon dies so quickly like that, it generally means there is a problem with one of the config files.

do the following first off
cat /etc/syslog.conf | grep -i mail
so we can see exactly where all of the mail logging is going.  Because there should be something in the logs saying what is causing the crash.  If we can't find anything there, then we'll move to the and config files
mkidoAuthor Commented:
I have been reading "" documentation, but up to now, I didn't find a clear method about switch from Sendmail to Postfix, nor I found easy command line test method to send email from Postfix.    
mkidoAuthor Commented:
The machine's OS version is Linux FedoraCore1 Yarrow (2003).
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mkidoAuthor Commented:
Thank you, Cyclops3590

I somehow understand the tight relationship between Sendmail and Postfix.   That is a very good suggestion for Email server newbie like me.   I am reading mail log at,


And I see that maillog tells everything about what is going on.   Let me check your command line too.   One moment.
mkidoAuthor Commented:
I looked into /etc/syslog.conf, and as I thought all mail log in my case goes to,


Based on the error messages in maillog and I did trial and errors, then finally sendmail sent my emails out.   So, I got what I wanted.   And I stopped working on Postfix.   Sendmail isn't bad, especially when a m4 macro is available ( file).  
Well at least its working.  I have absolutely no experience in Sendmail, but I know plenty of experts on EE do so if you ever need help in that area, don't hesitate
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