#yum install *dkim -y #yum install libopendkim-devel #grep opendkim /etc/passwd /etc/shadow /etc/group Output:- /etc/passwd:opendkim:x:498:498:OpenDKIM Milter:/var/run/opendkim:/sbin/nologin /etc/shadow:opendkim:!!:17410:::::: /etc/group:mail:x:12:mail,postfix,opendkim /etc/group:opendkim:x:498: #ls -l /etc/opendkim /var/run/opendkim/ Output:- drwxr-x--- 2 opendkim opendkim 4096 Dec 21 2016 keys -rw-r----- 1 opendkim opendkim 339 Dec 21 2016 KeyTable -rw-r----- 1 opendkim opendkim 1221 Dec 21 2016 SigningTable -rw-r----- 1 opendkim opendkim 378 Dec 21 2016 TrustedHosts ##generate Key for Singning # mkdir /etc/opendkim/keys/test.org #cd /etc/opendkim/keys/test.org #opendkim-genkey -d test.org -s groots #chmod 640 groots.private ##Create Key Table file vi /etc/opendkim/KeyTable groots._domainkey.test.org test.org:groots:/etc/opendkim/keys/test.org/groots.private ##Create Singning Table file cat /etc/opendkim/SigningTable ...