# yum -y install ssmtp Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile * base: mirror.kakao.com * extras: ftp.jaist.ac.jp * updates: ftp.jaist.ac.jp No package ssmtp available. Error: Nothing to do yum --enablerepo=extras install epel-release yum -y install ssmtp yum makecache Ãâó: https://www.ryadel.com/en/linux-install-configure-ssmtp-simple-alternative-postfix-sendmail-centos/