OpenNTP
ipv6 ntp pool - eu.ntp.sixxs.net
ubuntu/debian:
ln -s /etc/openntpd/ntpd.conf /etc/ntpd.conf
NTP
Setup Restrict values in ''ntp.conf''
see: http://www.thegeekstuff.com/2014/06/linux-ntp-server-client/
Modify the /etc/ntp.conf
file to make sure it has the following two restrict lines.
# Permit time synchronization with our time source, but do not # permit the source to query or modify the service on this system. restrict default kod nomodify notrap nopeer noquery restrict -6 default kod nomodify notrap nopeer noquery
The first restrict line allows other clients to query your time server. This restrict line has the following parameters
- noquery prevents dumping status data from ntpd.
- notrap prevents control message trap service.
- nomodify prevents all ntpq queries that attempts to modify the server.
- nopeer prevents all packets that attempts to establish a peer association.
- Kod – Kiss-o-death packet is to be sent to reduce unwanted queries
The value -6 in the second line allows forces the DNS resolution to the IPV6 address resolution. For more information on the access parameters list, Please refer to documentation on “man ntp_acc”