Postfix not sending/receiving -- Postfix general setup

daveburrow used Ask the Experts™
I'm a webmaster for a what is currently a small site hosted by a web hosting company. Plans are well underway to move to our own dedicated server, so I can have more control over what I can and can't do.  Unfortunately, all the linux stuff is new to me.

Problem: postfix setup eludes me.  -- once running, Postfix "sendmail" is only found if I am root, and once I do a "sendmail" command, the email never makes it out.

Clue: /var/log/maillog has multiple entries for "Connection refused" -- having the expected increasingly defered timestamp interval at each attempt.

Despite the "just change these three fields and VOILA!" description of the setup, I'm way to green and new to Linux, and some of even the basic assumptions can't be made.

From what I understand so far -- sendmail comes up on boot of my RedHad 8.0 server and my RedHat 9.0 local development box. I can stop sendmail via "service sendmail stop" and start Postfix via "service postfix start" --- I'll get that on startup soon -- not the priority. For now the discussion need to be relative to the server only, as I'm having trouble getting my development box to see the internet.

I have webmin running on the server -- if that helps.

rpm -qa reports the following mail oriented packages:


As always -- any help is appreciated.....

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I'll listen here to learn a bit, but i'm getting a bit confused by your setup... If you use Postfix, you don't
need to run sendmail, too, do you? I just set up a mail server and chose to run Postfix and not start
sendmail. Works excellently, once the Postfix config file was adjusted to our needs.

Are you looking for a command-line command for sending one mail when Postfix is running or what?


... wish it was a simple request....

although I'm aware of the vulgarity of vagueries... I'm kinda looking for "all things Postfix"

To be specific -- I need to replace the functionality of all things my Web Hoster (virtual host) gives me as I move to a dedicated server -- please read "absolutely green" webmaster --  it fits like an undersized wetsuit!


1) I've subsequently installed webmin and gotten Postfix to be the default to replace sendmail as the MTA that starts up on boot
2) the only "sendmail" command I can find is in /usr/sbin as

lrwxrwxrwx    1 root     root           21 May 15 09:53 sendmail -> /etc/alternatives/mta

Is this normal?? If so, why is it limited (uid / guid) to root only??  

OK, stupidest of all questions thus far -- how am I SUPPOSED to setup an SMTP server and POP3 service??


OK -- more info

[root]: /var/log ==> mailq
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
34AE84819F      341 Sat Aug 30 14:10:24  root@<altered....>
     (connect to <altered>[]: Connection refused)

-- 0 Kbytes in 1 Request.


Connection is refused --- what parameters affect connection??

BTW -- the altered target site was the virtual site I'm moving from......
Microsoft Azure 2017

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"OK, stupidest of all questions thus far -- how am I SUPPOSED to setup an SMTP server and POP3 service??"

Not a stupid question.

OK. I can't say I'll give you the answers you want, but, in principle:
You get an SMTP daemon when you install a Linux distro like RedHat - sendmail by default, but you can change
to Postfix, for instance, by running a GUI procedure. Easy.

This SMTP server will relay for you, on the host in question. To get it to relay for others, you need to configure
the SMTP server to relay for: local host/subnet/defined hosts/everyone. This is done by making changes in the
configuration file. You use it when you run PINE or Mozilla mail; the SMTP server is set to localhost.

POP3 is a service that is disabled by default on RH distros. Enabling this service gives you a POP3 server. Users
need to be users on the system. There is a possibility to set up "mail only" users, I'm told, but the procedure is
not clear to me.

You may get a lot of more useful comments if you make a Q  in the Linux TA and link it to this one.

MarkLead Sales Engineer - Public Sector

daveburrow -

I run nothing but Postfix on all of my companies hosted mail servers. I have it integrated with SPAM and virus filtering software, and actually use for hosted mail scanning services for my customers. I tell you all of this only in the hopes of making you feel at ease with what the software is capable of...

Now - on to your issues.

Please have a look at these other Postfix-related questions to see if anything in here helps you. If it does, great. If not, please let me know what's missing.


Ok, doing some cleanup on some really old questions --- turns out somewhere along the way, I had altered the smtpd to listen on a different port. I've long ago put it back to 25 and it all works well. Giving the points to "rid" because, by the time I got back to this, it was solved and the links given by "mburdick" created only JSP errors... sorry.

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