http://www.pool.ntp.org/zone/kr
Korea — kr.pool.ntp.org
There are not enough servers in this zone, so we recommend you use the Asia zone (asia.pool.ntp.org):
server 0.asia.pool.ntp.org
server 1.asia.pool.ntp.org
server 2.asia.pool.ntp.org
server 3.asia.pool.ntp.org