Configure NTP on AIX

The following information outlines the steps necessary to configure a basic NTP setup between an NTP client and server on AIX.

On server execute below commands in sequence

1) Verify that you have a suitable NTP server. Enter:

# lssrc -ls xntpd

NOTE: Sys peer should show a valid server or 127.127.1.0.

If the server is "insane", you will need to correct it by adding a server line to /etc/ntp.conf and restarting xntpd.
This can be done by following these steps:

# vi /etc/ntp.conf
Add:
server 127.127.1.0

Double check that "broadcast client" is commented out.

# stopsrc -s xntpd
# startsrc -s xntpd

NOTE: If the server runs databases, use the -x flag to prevent the clock from changing in a negative direction. Enter the following:

# startsrc -s xntpd -a "-x"

2) Repeat Step 1 to verify that the server is synced. This process can take up to 12 minutes.

On client verify that you have a server suitable for synchronization
Enter:

# ntpdate -d ip.address.of.server

The offset must be less than 1000 seconds for xntpd to sync.
If the offset is greater than 1000 seconds, change the time manually on the client and run the ntpdate -d again
If you get the message, "no server suitable for synchronization found", verify xntpd is running on the server(see above) and that no firewalls are blocking port 123.

3) Specify your xntp server in /etc/ntp.conf, enter:

# vi /etc/ntp.conf

(Comment out the "broadcastclient" line and add server ip.address.of.server prefer.)
Leave the drift file and trace file at their defaults.

4) Start the xntpd daemon:

# startsrc -s xntpd

(Use the -x flag if it is appropriate for your environment.)
Uncomment xntpd from /etc/rc.tcpip so it will start on a reboot.

# vi /etc/rc.tcpip

Uncomment the following line:

5) start /usr/sbin/xntpd "$src_running"

If using the -x flag, add "-x" to the end of the line. You must include the quotes around the -x.
Verify that the client is synced.

# lssrc -ls xntpd

NOTE: Sys peer should display the IP address or name of your xntp server. This process may take up to 12 minutes.