Category: Mail

To allow a web server to send email through PowerMTA with out autentication, you need to edit PowerMTA configuration file

vi /etc/pmta/config

Add a source entry for the IP address that you need to allow relaying mails

    always-allow-relaying yes
    smtp-service yes

Replace IP_ADDRESS with IP address of web server that you need to allow sending email with out autentication.

Restart PowerMTA

systemctl restart pmta

With out source entry, if you try to sent email, you will be rejected with error “550 5.7.1 relaying denied for recipient”.

Example using swaks

root@lab:~# swaks --to [email protected] --server smtp1.serverok.in --port 2525
=== Trying smtp1.serverok.in:2525...
=== Connected to smtp1.serverok.in.
<-  220 smtp1.serverok.in ESMTP service ready
 -> EHLO lab.serverok.in
<-  250-smtp1.serverok.in says hello
<-  250-ENHANCEDSTATUSCODES
<-  250-PIPELINING
<-  250-CHUNKING
<-  250-8BITMIME
<-  250-AUTH CRAM-MD5
<-  250-AUTH=CRAM-MD5
<-  250-XACK
<-  250-SIZE 0
<-  250-VERP
<-  250-SMTPUTF8
<-  250 DSN
 -> MAIL FROM:
<-  250 2.1.0 MAIL ok
 -> RCPT TO:
<** 550 5.7.1 relaying denied for recipient in "RCPT TO:"
 -> QUIT
<-  221 2.0.0 smtp1.serverok.in says goodbye
=== Connection closed with remote host.
root@lab:~# 

See PowerMTA

To change SMTP port in PowerMTA, edit file

vi /etc/pmta/config

Find line starting with

smtp-listener

This line specify port used by PowerMTA server. You can change the power on this line. If you need PowerMTA listen to multiple ports, duplicate the line and change port, this will make PowerMTA work using both ports.

smtp-listener 0/0:2525
smtp-listener 0/0:25

This will make PowerMTA work on both port 25 and port 2525

After editing /etc/pmta/config, you need to restart PowerMTA with

systemctl restart pmta

See PowerMTA

Once you have PowerMTA installed, you need to create SMTP user. To create an SMTP user, edit file

vi /etc/pmta/config

Find

#
#    password "changeme"
#

Add below

    password "SMTP_PASSWORD_HERE"
    source {smtpuser-auth}



    smtp-service yes
    always-allow-relaying yes
    require-auth true
    process-x-virtual-mta yes
    default-virtual-mta vmta-1
    remove-received-headers true
    #add-received-headers false
    hide-message-source true



    #smtp-source-host 79.137.44.176 smtp1.serverok.in
    #domain-key default,smtp1.serverok.in,/etc/pmta/default.smtp1.serverok.in.pem
    
    max-msg-rate 100/h
    

In above code, replace SMTP_USERNAME_HERE and SMTP_PASSWORD_HERE with SMTP username and password you need.

in vmta-1, domain-key line that is commented out is used to Enable DKIM signing of out going emails.

Resatrt PowerMTA

systemctl restart pmta

See PowerMTA