Before building sendmail, we need to create users, groups and directories that sendmail uses with the following commands: groupadd -g 18 smmsp && groupadd -g 19 mail && useradd -g smmsp -G mail -u 18 smmsp && chmod 1777 /tmp && chmod 1777 /var/mail && mkdir /var/spool/mqueue Install sendmail with the following commands: cd sendmail && sh Build && cd ../cf/cf && cp generic-linux.mc sendmail.mc && mkdir /etc/mail && sh Build sendmail.mc && sh Build install-cf && cd ../../ && sh Build install