Unable to send email from CentOS machine

sysmicuser · 11-07-2018, 06:27 PM

Can I seek your assistance to see how can I use mailx or mail on my CentOS 7.5?

I was able to send emails before but now I am not.

Is there any config file where I need to input the mail server settings?

Some configuration from the CentOS server is as below

Code:

[jim@centos74.master /data/OnlyOnMyPC/ansible]nmap localhost | grep -i smtp
25/tcp   open  smtp
[jim@centos74.master /data/OnlyOnMyPC/ansible]nmap centos74.master | grep -i smtp
[jim@centos74.master /data/OnlyOnMyPC/ansible]cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
[jim@centos74.master /data/OnlyOnMyPC/ansible]hostname
centos74.master
[jim@centos74.master /data/OnlyOnMyPC/ansible]ps -ef|grep -i mail
jim      28723  4607  0 11:24 pts/0    00:00:00 grep --color=auto -i mail
[jim@centos74.master /data/OnlyOnMyPC/ansible]ps -ef|grep -i mail|grep -v grep
[jim@centos74.master /data/OnlyOnMyPC/ansible]

[jim@centos74.master /data/OnlyOnMyPC/ansible]telnet x.y.com.au 25
Trying [IP Address ] ...
Connected to x.y.com.au.
Escape character is '^]'.
220 x.y.com.au
quit
221 Service closing transmission channel
Connection closed by foreign host.
[jim@centos74.master /data/OnlyOnMyPC/ansible]

I could telnet from VM to SMTP server on port 25.

Appreciate your assistance in advance

Thanks

ShadowCat8 · 11-07-2018, 07:34 PM

Greetings,

Well, if you are using mailx, then you should have a config file for it to read... usually ~/.mailrc

And, from the man page on how to create the settings for an account:

Quote:

Originally Posted by man mailx

account
(ac) Creates, selects or lists an email account. An account is formed by a group of commands, primarily of those to set variables. With two arguments, of which the second is a `{', the first argument gives an account name, and the following lines create a group of commands for that account until a line containing a single `}' appears. With one argument, the previously created group of commands for the account name is executed, and a folder command is executed for the system mailbox or inbox of that account. Without arguments, the list of accounts and their contents are printed. As an example,

Code:

                  account myisp {
                      set folder=imaps://mylogin@imap.myisp.example
                      set record=+Sent
                      set from="myname@myisp.example (My Name)"
                      set smtp=smtp.myisp.example
                  }

creates an account named `myisp' which can later be selected by specifying `account myisp'.

Hope that helps. Let us know.

sysmicuser · 11-07-2018, 09:35 PM

It appears that my initial command might have been mail instead of mailx:

Code:

[root@centos74.master ~]find / -xdev -type f -name "mailrc"
[root@centos74.master ~]find / -xdev -type f -name ".mailrc"

The above indicates that I do not have .mailrc, is there any global configuration file/settings?

dc.901 · 11-08-2018, 06:05 AM

What happens if you use mail? Here is an example:

Code:

echo "Test email from CentOS - body" | mail -s "mail subject" -r replytoemail@mydomain.com <your email address here>

scasey · 11-08-2018, 08:54 AM

What has changed since you were able to send mail?

sysmicuser · 11-12-2018, 10:10 PM

@dc.901 No success. I know the problem but I don't know the solution. Somehow emails are going through cloud mail server (Office 365) instead of the internal mail server. I don't know what that is happening but I can clearly see it happening.

scasey · 11-12-2018, 11:57 PM

What is the internal mail server? Sendmail, postfix, qmail...?

sysmicuser · 11-13-2018, 05:32 PM

@scasey, the Internal mail server is a product as a Service from https://www.smartertools.com/

I'm just advised that there is an authentication on the internal mail server and they have created a service account for me. How should I use it? I don't know much about it.

scasey · 11-13-2018, 06:26 PM

Quote:

Originally Posted by sysmicuser

@scasey, the Internal mail server is a product as a Service from https://www.smartertools.com/

I'm just advised that there is an authentication on the internal mail server and they have created a service account for me. How should I use it? I don't know much about it.

Have you reviewed their documentation and/or asked them for support?
I don't know anything about it or how to use it, but there looks to be pretty good documentation on that site.

sysmicuser · 11-13-2018, 06:56 PM

@scasey, Thanks for that, I can figure that out, my concern is how to tell CentOS not to use O365 but to use the internal mail server. How to configure that. There must be some settings for that?

sysmicuser · 11-13-2018, 07:04 PM

An interesting thing is another Centos machine is sending email correct, although they are being received in Junk folder, but at least its working.

chrism01 · 11-14-2018, 09:16 PM

Have you looked at /var/log/maillog ?
On your system, if its RHEL/Centos 6 or 7, it defaults to installing postfix mailserver service (smtp).

You use mailx to send to another serve, but it has to go through a local smtp eg postfix - hence the log.

dc.901 · 11-15-2018, 06:19 AM

Quote:

Originally Posted by sysmicuser

An interesting thing is another Centos machine is sending email correct, although they are being received in Junk folder, but at least its working.

Is this another Centos machine also in DMZ network? And how exactly are you sending emails from this another server (mail command, telnet, or your application)?
As chrism01 mentioned, review your logs to see what's happening.
After you send emails from both servers, what is output of mailq command?