Technical data

4. Packages
Only time servers in the internet which are reachable by the default route (0.0.0.0/0) can be
used, because only the default route changes chrony into online mode. As an ethernet router
with no DSL or ISDN circuits configured, chrony acts permanently in online mode.
Disclaimer: The author gives neither a guarantee of functionality nor is he liable for any
damage or the loss of data when using OPT_CHRONY.
4.3.1. Configuration of OPT_CHRONY
The configuration is made, as for all fli4l packages, by adjusting the file
path/fli4l-3.10.1/ config /chrony.txt to meet the own demands. However almost all vari-
ables of OPT_CHRONY are optional. Optional means, the variables could, but need not be
in the config file. Thus the chrony config file is almost empty and all optional variables have
a usefull setting by default. To use different settings, the variables must be inserted into the
config file by hand. Furthermore the description of every variable follows:
OPT_CHRONY Default: OPT_CHRONY=’no’
The setting ’no’ deactivates OPT_CHRONY completely. There will be no changes made
on the fli4l boot medium or the archive opt.img. Further OPT_CHRONY basically does
not overwrite other parts of the fli4l installation with one exception. The paket filter file
which is responsible for not counting the traffic coming from the outside (to make sure
fli4l will drop the line for sure, when reaching the hangup time), will be exchanged. The
new paket filter file ensures, that chrony-traffic doesn’t count for the hangup time.
To activate OPT_CHRONY, the variable OPT_CHRONY has to be set to ’yes’.
CHRONY_TIMESERVICE Default: CHRONY_TIMESERVICE=’no’
With CHRONY_TIMESERVICE an additional protocol to transfer time informations can be
invoked. It’s only neccesary when the local hosts can’t deal with NTP. It is conform to
RFC 868 and uses port 37. If possible, prefer NTP.
Many thanks to Christoph Schulz, who provided the program srv868.
CHRONY_TIMESERVER_N Default: CHRONY_TIMESERVER_N=’3’
CHRONY_TIMESERVER_N sets the number of reference time servers chrony uses. Add the
same number of CHRONY_TIMESERVER_x variables. The index x must be increased up to
the total number.
The basic setting uses up to three time servers from pool.ntp.org (Page 92).
CHRONY_TIMESERVER_x Default: CHRONY_TIMESERVER_x=’pool.ntp.org’
With CHRONY_TIMESERVER_x an own list of internet time servers can be made. Either IP
or DNS hostnames are possible.
CHRONY_LOG Default: CHRONY_LOG=’/var/run’
CHRONY_LOG is the folder where chrony stores informations about the BIOS clock and the
time adjustments. In almost any cases, this should not be altered.
CHRONY_BIOS_TIME Default: CHRONY_BIOS_TIME=’utc’
To analyze the time of the BIOS clock (RTC = real time clock) correctly, CHRONY_BIOS_TIME
provides if the clock runs at local ’local’ or universal time ’utc’ (UTC - Universal Co-
ordinated Time).
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