Open the aliases in the text editor:Continue reading “Redirecting mail for the root user”
First, configure the Zabbix agent.
Create a file (in the nano editor, press Ctrl+X to exit, and y/n to save or discard changes):
Add to it:
UserParameter=postfix.maildrop, find /var/spool/postfix/maildrop -type f | wc -l UserParameter=postfix.deferred, find /var/spool/postfix/deferred -type f | wc -l UserParameter=postfix.incoming, find /var/spool/postfix/incoming -type f | wc -l UserParameter=postfix.active, find /var/spool/postfix/active -type f | wc -l UserParameter=postfix.queue, mailq | grep -v "Mail queue is empty" | grep -c '^[0-9A-Z]'
Alternatively, you can simply add the lines above to the Zabbix agent configuration file.
Also open the Zabbix agent configuration file:
We will allow Zabbix agent to work as root with the user specifying:
Restart the Zabbix agent to apply the changes:
sudo /etc/init.d/zabbix-agent restart
Now go to the Zabbix server.
Create a Postfix template, add data items to it, specifying the type – Zabbix agent, and the keys: postfix.maildrop, postfix.deferred, postfix.incoming, postfix.active, postfix.queue.
Create graphics for the created data items.
You can also create a data item that counts the number of Postfix processes by specifying the type – Zabbix agent, and the key:
Also create a trigger that tells when processes 0.
Download the ready template here – Zabbix шаблон для Postfix
Postfix — mail transfer agent (MTA) with open source.
Assume that the IP address of the server is configured with a domain name, from which the mail will be sent in the future.
Switch directly to the root user:
Proceed to install Postfix.
To install in Ubuntu, perform:
apt-get update apt-get install postfix
For installation in CentOS:
yum install postfix
During the installation, some questions will be asked.
1) Choose the “Internet site”
2) Specify the fully qualified domain name server (FQDN), for example example.com
After that Postfix will start working.
Configuration files are usually found in /etc/postfix.
We can look at the status/restart/stop/start Postfix commands:
service postfix status service postfix restart service postfix stop service postfix start
If necessary, you can reconfigure by typing the following command:
Let’s see if the ports are used:
netstat -na | grep LISTEN | grep 25 netstat -na | grep LISTEN | grep 587
You can perform an automatic check:
Let’s try to send the letter to the specified address (after the command we will type the desired text and put a point for completion):
sendmail -v firstname.lastname@example.org
You can search the logs for the information you need via grep, for example, find all the lines that contain email@example.com:
grep firstname.lastname@example.org /var/log/mail.log
You can also connect from another host to the postfix port via telnet and make sure that it is running.
For diagnostics, you can observe the connections using tcpdump:
tcpdump port 25 tcpdump port 587
If there are more than one IP on the server, and the domain is only on one, we will specify from which IP the sending will be done:
sudo nano /etc/postfix/main.cf smtp_bind_address = 22.214.171.124
You can also specify on which interfaces Postfix will work:
#inet_interfaces = all inet_interfaces = 127.0.0.1
Restart Postfix to apply the changes:
sudo /etc/init.d/postfix restart
To allow the sending of messages on the mail server without encryption via port 25, you need to open the Postfix configuration file, for example, in the nano editor (in which Ctrl+X to exit, y/n to save or cancel changes):
sudo nano /etc/postfix/main.cf
And uncomment two lines:
smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous
And leave the commented line:
Reload Postfix to apply the changes:
sudo service postfix restart
After that it will be possible to send messages via SMTP through port 25 without SSL, and as usual through 587 with SSL.
I noticed once on one server that Postfix does not always send mail, the logs had the following error:
warning: host NAME[192.168.5.5]:25 greeted me with my own hostname NAME
After seeing the host name:
Found that it is not correct and coincides with that on which the mail is sent!
Changed the host name to the correct one in the following files (in the nano editor Ctrl+X to exit, y/n to save or cancel changes):
sudo nano /etc/hostname sudo nano /etc/postfix/main.cf sudo nano /etc/hosts
Done, after that the error did not appear and the mail was successfully delivered.