Hi Dude, today i will post simple article about install postfix Ubuntu 20.04. Ok lets go. Postfix is open source mail transport agent with many feature.
#1. Setup Hostname Server
In this server, im using server name smtp.habibza.in. Just run simply command like this.
hostnamectl set-hostname smtp.habibza.inAfter that, jump to /etc/hosts and edit
#vim /etc/host
127.0.0.1 localhost
103.223.224.124 smtp.habibza.in smtpReboot for a while to make sure the host has changed perfectly.
#2. Install Postfix in Ubuntu 20.04
In ubuntu server, run the following command below.
sudo apt-get update
sudo apt-get install postfix -yBy default, will appear conversation below. We will be asked to select a type for mail configuration. Select “Internet Site”.
No configuration: The installation process will not configure any parameters.Internet Site: Setup Postfix for sending emails to other MTAs and receiving email from other MTAs.Internet with smarthost: Setup postfix to receive email from other MTAs, but using another smart host to relay emails to the recipient.Satellite system: Setup smart host for sending and receiving email.Local only: Setup emails are transmitted only between local user accounts.
Press OK. Input hostname full FQDN.
After finish installed, Postfix will be automatically started and a /etc/postfix/main.cf file will be generated.
#3.Check status Postfix.
systemctl status postfix
Check binary postfix installed.
dpkg -L postfix | grep /usr/sbin/
Output:
/usr/sbin/postalias
/usr/sbin/postcat
/usr/sbin/postconf
/usr/sbin/postdrop
/usr/sbin/postfix
/usr/sbin/postfix-add-filter
/usr/sbin/postfix-add-policy
/usr/sbin/postkick
/usr/sbin/postlock
/usr/sbin/postlog
/usr/sbin/postmap
/usr/sbin/postmulti
/usr/sbin/postqueue
/usr/sbin/postsuper
/usr/sbin/posttls-finger
/usr/sbin/qmqp-sink
/usr/sbin/qmqp-source
/usr/sbin/qshape
/usr/sbin/rmail
/usr/sbin/sendmail
/usr/sbin/smtp-sink
/usr/sbin/smtp-source
#4. Check Allow TCP Port 25 (inbound) in Firewall.
We have to open port 25 TCP incoming in firewall. (If we activated firewall UFW in server).
sudo ufw allow 25/tcp#5. Check Port 25 Outbound.
Simply way to check port 25 outbound is using telnet. We use telnet port 25 to other server mail, like google gmail mx.
sudo apt install telnettelnet gmail-smtp-in.l.google.com 25
If it’s not blocked, you would see messages like below.
Trying 74.125.68.26...
Connected to gmail-smtp-in.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP y22si1641751pll.208 - gsmtp
If port 25 (outbound) is blocked or something worng, you would see something like:
Trying 2607:f8b0:400e:c06::1a...
Trying 74.125.195.27...
telnet: Unable to connect to remote host: Connection timed out.
#6. Setting Postfix and Tune it.
By default, Postfix SMTP server uses the OS’s hostname.
Find the myhostname parameter and set mail.yourdomain.com as the value. It’s not recommended to use the apex domain yourdomain.com as myhostname.
myhostname = smtp.habibza.insudo systemctl restart postfix#7. Creating Email Alias.
sudo nano /etc/aliasesBy default, there are only two lines in this file.
# See man 5 aliases for format
postmaster: rootThe first line is a comment. Normally we don’t use the root email address. So you can add the following line. Replace username with your real username.
root: username
This way, emails for [email protected] will be delivered to [email protected]. Now you can save and close the file. Then rebuild the alias database with the newaliases command
sudo newaliases#8. Using IPv4 Only
By default, Postfix uses both IPv4 and IPv6 protocols, as can been seen with:
postconf inet_protocolsOutput:
inet_protocols = all
If your mail server doesn’t have a public IPv6 address, it’s better to disable IPv6 in Postfix to prevent unnecessary IPv6 connections. Simply run the following command to disable IPv6 in Postfix.
sudo postconf -e "inet_protocols = ipv4"Then restart Postfix.
sudo systemctl restart postfix#9. Increase Attachment Size Limit
By default, the attachment cannot be larger than 10MB, which is indicated by the message_size_limit parameter.
postconf | grep message_size_limitOutput:
message_size_limit = 10240000This parameter defines the size limit for emails originating from your own mail server and for emails coming to your mail server.
To allow attachment of 50MB in size, run the following command.
sudo postconf -e message_size_limit=52428800message_size_limit=52428800 thats mean maximum size of email is 50 mb.
#10. Setting Postfix Not Open Relay.
This important part setting postfix. We have to make sure sure that our setting Postfix is not open relay.
Just edit /etc/postfix/main.cf and find mynetworks.
vim /etc/postfix/main.cfSee default mynetworks.
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128Change to:
mynetworks = 127.0.0.0/8, 103.224.124.124/32, 192.168.10.0/24Where 103.224.124.124/32, 192.168.10.0/24 is IP that allow to using this server to sent email.
That is step by step install postfix Ubuntu 20.04 and tuning deployment in Ubuntu. Please feel free for comment. Maybe usefull.
