#from epel repo
yum -y install opendkim
chkconfig opendkim on
cd /etc/opendkim/keys
opendkim-genkey -vd mail.server.com
opendkim-genkey: generating private key
opendkim-genkey: private key written to default.private
opendkim-genkey: extracting public key
opendkim-genkey: DNS TXT record written to default.txt
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