You should install pure-ftpd
yum install pure-ftpd
If you are using Fedora also pure-ftpd-selinux

mkdir /webs/web1/public_html
chown web1:web1 /webs/web1/public_html
pure-pw useradd web1_ftp -u web1 -g web1 -d /webs/web1/public_html
pure-pw mkdb
pure-pw list
web1_ftp is your virtual user name

You should remember enable: PureDB /etc/pure-ftpd/pureftpd.pdb in your pure-ftpd main configuration file and disable anonymous access: NoAnonymous yes