i must use a third-party yum repository to install it.
# cd /etc/yum.repos.d/
# wget http://centos.karan.org/kbsingh-CentOS-Extras.repo
# rpm –import http://centos.karan.org/RPM-GPG-KEY-karan.org.txt
# vi /etc/yum.repos.d/kbsingh-CentOS-Extras.repo
and set enabled=1
and set enabled=1
and then you can instal proftpd with yum
# yum install proftpd