Setup ntpd on Linux (for serving time)
--------------------------------------
2006-02-17


# Prohibit general access to this service.
restrict default nomodify notrap noquery

# Permit all access over the loopback interface.  This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1 

# -- CLIENT NETWORK -------
# Permit systems on this network to synchronize with this
# time service.  Do not permit those systems to modify the
# configuration of this service.  Also, do not use those
# systems as peers for synchronization.
restrict 192.168.1.0 mask 255.255.255.0 notrust nomodify notrap

# --- OUR TIMESERVERS ----- 
# May need to use IP addresses

server clock1.redhat.com
server clock2.redhat.com
server clock3.redhat.com

# --- NTP MULTICASTCLIENT ---
#multicastclient			# listen on default 224.0.1.1
# restrict 224.0.1.1 mask 255.255.255.255 notrust nomodify notrap
# restrict 192.168.1.0 mask 255.255.255.0 notrust nomodify notrap

# --- GENERAL CONFIGURATION ---
server	127.127.1.0 
fudge	127.127.1.0 stratum 10	

#
# Drift file.
driftfile /var/lib/ntp/drift
broadcastdelay	0.008

# Authentication delay.
authenticate yes

# Keys file.
keys		/etc/ntp/keys


Notes:
chkconfig ntpd on
ntpdate clock1.redhat.com
service ntpd start


Setup ntpd on Linux (for client time)
-------------------------------------

vi /etc/ntp.conf

# --- OUR TIMESERVERS ----- 
restrict default notrust nomodify notrap
OR restrict ip.ad.dr.ess (of mytime.server.com)
server mytime.server.com

vi /etc/ntp/step-tickers
mytime.server.com  #may need to use IP addresses


Troubleshooting NTP
-------------------

service ntpd restart

Wait 20 minutes then run 'ntpdc -p -n' and 'ntptime' to check what's going on

check "reach" column in ntpdc output.  0 is bad... 377 is good  (octal)

the "poll" column will show seconds between polls