|Domain Time DTLinux|
DTLinux configuration is simple and straightforward. All configuration (with the exception of configuring the
dtlinux.keys file for symmetric authentication) is done by editing the dtlinux.conf file.
See a sample here: dtlinux.conf.sample.txt.
Both the dtlinux.conf and dtlinux.keys files are heavily commented and are the primary documentation for DTLinux. You should always keep a copy of the original
distribution files available for reference in case the comments in your running copies are inadvertently removed during editing.
This online documentation page merely highlights a few of the topics for additional discussion.
The dtlinux.conf file
The file is divided into functional sections:
- NTP and DT2 Time Sources
This section covers how to configure DTLinux to obtain time from NTP and/or DT2 time sources.
You can manually specify the sources in the dtlinux.conf file and DTLinux can also obtain a list
of sources from DHCP options.
Selecting the correct time sources are critical for accurate timing.
The Internet time sources specified in the default .conf file are intended as examples only. Choose servers
that are optimal for your environment. Stable time sources on a local subnet are best.
See the Planning for effective time distribution
for help making the right choice.
- Loop Variables
You can set the time check intervals using the parameters in the section. You also control whether to keep
ntp-style loopstats and peerstats files.
A loop:checkInterval of 60 is recommended if you are using PTP to allow PTP time to collect enough valid samples
to analyze statistically for best performance. Otherwise, if using NTP or DT2, set the value low enough to
acheive the accuracy you require. Setting the value too low just increases overhead and network traffic.
Also, set a reasonable loop:errorInterval. The value should normally be 30 seconds or less. This affects the period
between DTLinux detecting a loss of sync with time sources and when it retries a connection. A relatively short error interval
is desireable to restore sync quickly when sources become available again.
The loop:checkAll setting determines whether all the configured NTP and DT2 time sources are included and analyzed in each time check
or if the list is used for fallback, where the first server is used until it fails, at which point the next machine in the list is tried.
You may set the log level to Trace (log:logLevel = Trace) if you want to see the details on which machines are used in
each time synchronization.
- PTP Settings
Use this section to enable/disable PTP and set its basic parameters.
See the PTP Profiles section of the main PTP page for
information on which PTP Profiles DTLinux supports.
Be sure to use DTLinux's ability to view available PTP Masters when troubleshooting synchronization issues:
From Domain Time Manager:
Choose Graphs & Statistics -> Open PTP Statistics & Masters from the Manager menu to disply the PTP Statistics page.
Then click the PTP Masters link on that page to see the PTP Masters list.
Domain Time II Real-Time Alerts
If you are using Domain Time II Audit Server, we suggest you enable Real-Time Alerts in this section, even if you haven't
yet configured any Real-Time Alerts in Audit Server. This will cause the DTLinux machine to display in the Real-Time Alerts
page of Manager, giving you up-to-date information on synchronzation status and accuracy.
If you use cloned OS images to install machines, please read this article
from our knowledgebase about configuring Domain Time properly on your clone image.
License: Commercial Proprietary (registration required)
This section describes the evaluation period and how to register the software. The section will
be removed when the software is registered.
The dtlinux.keys file
This file contains the authentication keys used for the DT2, NTP, and/or PTP v2.1 protocols.
It's also referred to as your keyring. It's located in the /etc/opt/domtime/ folder.
The keyring may contain a combination of trusted and untrusted keys. A trusted key means the key
is available to be selected by the component, but trusted keys for DT2 and NTP are not active
until their key number is specified when configuring a DT2 or NTP time source in the time sources
list of the dtlinux.conf file (i.e. timesource = 192.168.1.3 protocol NTP key 5).
Trusted keys for PTP v2.1 aren't active unless PTP Security has been enabled. Untrusted keys are ignored.
Here are values from a sample keyring, with MD5 keys available for use by DT2 or NTP, and SHA256 keys available for PTP v2.1:
The Trustedkey line in the file specifies which keys in the keyring are trusted, i.e.:
Trustedkey 1 2 3 4 9909
The file also contains additional settings required for PTP v2.1 authentication.
ptpSPP sets the Security Parameter Pointer (SPP). PTP v2.1 requires that Masters and Slaves use the same SPP
value to be able to authenticate. The SPP stored in the keyring may either be zero (which acts like a wildcard) or must match what
the grandmaster sends. If there is a potential for your Slaves to discover more than one Master (such as with a fallback server),
we recommend you use the wildcard setting (0) to avoid synchronization failure if each server has a different SPP.
These entries specify the key number of the secret that Masters use for signing outgoing packet types. They are included here
for compatibility when importing the .keys file into Domain Time Server. These parameters are ignored by Domain Time Client
and DTLinux :
These entries specify the key number of the secret used for signing packet types sent by the Slave:
Sharing the keyring file.
For symmetric authentication to work, the keyring must be shared among all devices that wish to use it. The dtlinux.keys file
uses a format compatible with most time daemons (i.e. ntpd's ntp.keys, chrony's chrony.keys, etc.). You can usually simply
copy the /etc/opt/domtime/dtlinux.keys file to your target system (rename it if necessary).
/etc/opt/domtime/dtlinux.keys file from one DTLinux machine to another.
You may also share the dtlinux.keys file with Domain Time Servers and Clients on Windows (and vice versa). Use the
Import/Export link on the Symmetric Keys
property page of the Server or Client's applet to import or export the .keys file.
If you are using Domain Time II Manager, you can use the Reset Keyring
function to push out the keyring to all of your Windows Servers and Clients and DTLinux machines at once. The
Reset Keyring function uses the
keyring of the Domain Time Server on which Manager is installed. So, to easily share a DTLinux machine's keyring among all of your other
Domain Time systems, you'd import the keyring file into
Manager's Domain Time Server and then select the machines you want to update and use the
Reset Keyring command from the right-click context menu.
Proceed to the Managing DTLinux Remotely page
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