###NTP####

/etc/ntp.conf
server

to sync time to the internet time server

service ntpd stop
ntpdate 0.fedora.pool.ntp.org
service ntpd start

to check ntp

ntpq -p

set iptables

iptables -I INPUT -m udp -p udp --dport 123 -j ACCEPT
iptables -I INPUT -m tcp -p tcp --dport 123 -j ACCEPT