Setup DKIM on Postfix Mail server.txt

Setup DKIM on Postfix Mail server.txt

$ MYDOMAIN=yourdomain.com
$ mkdir -p /etc/mail/dkim-keys/$MYDOMAIN
$ cd /etc/mail/dkim-keys/$MYDOMAIN
$ opendkim-genkey -t -s mail -d $MYDOMAIN

# if opendkim-genkey command is not found, install it#
# Eg: With Centos 7:
$ rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
$ sudo yum install -y opendkim

# 2 news file will be generated: mail.private and mail.txt

# add this line to /etc/mail/dkim-key
$ vim /etc/mail/dkim-key
->
*@you:you:/etc/mail/dkim-keys/yourdomain.com/mail.private
# for eg:
*@ec2-user:ec2-user:/etc/mail/dkim-keys/yourdomain.com/mail.private

# Edit DKIM configuration file /etc/opendkim.conf and update below values in configuration file.
$ vim /etc/opendkim.conf
->
Domain             yourdomain.com
KeyFile            /etc/mail/dkim-key
Selector           mail
Socket             inet:8892@localhost

# Now edit POSTFIX configuration file /etc/postfix/main.cf and add following values at the end of file
$ vim /etc/postfix/main.cf
->
milter_default_action = accept
milter_protocol = 2
smtpd_milters = inet:localhost:8892
non_smtpd_milters = inet:localhost:8892

# Configure DNS Entry using info from mail.txt
...

# Set permission
$ sudo chown opendkim:opendkim /etc/mail/dkim-key
$ sudo chmod 400 /etc/mail/dkim-key

# Restart Service
$ sudo service opendkim restart
$ sudo service postfix restart

# Verify DKIM
$ mail -vs "Test DKIM" test_email@gmail.com < /dev/null