NTP server in a environment without outside connection

  • Hi all,

    I would like to know if this following situation is possible:

    I often have to install infrastructures which require an NTP server in order to make synchronization. I always to have this in a lab environment before to implement it in a production environment. So there are no access to others stratum in order to retrieve the time.
    Is there a possibility with pfsense to be the stratum 1 and set by myself the clock without asking to another stratum ?

    Thank you in advance!

    Best regards,


  • It's not clear whether you mean no external connection in the lab or in production.

    For pfSense in a lab/test environment it may be acceptable to have no external server as a higher stratum NTP source and to make the clients sync to pfSense.  The pfSense server wouldn't have to be "Stratum 1" to achieve that.  However the clock on the pfSense server will probably drift significantly over time.  If you just need to make sure the clients are sync'ing successfully, that may not matter.

    In production it would probably be unacceptable not to have an external reference.

  • I mean, it's a lab environment. It's not yet in the production environment. We do the installation (which needs the NTP server) in a lab environment prior to do it in the production environment. We cannot have an access to Internet without being in the production environment, that's why I'm asking if pfSense could be a NTP server without connection to Internet.

    So I can setup pfSense to be the NTP server and he can give the time to the clients. On what will pfSense base its time? Can I setup the time that I want ?

    Thanks for the responses.



  • I would want to test my setup with an internet connection, but that is your choice.
    NTP knows an orphan mode and you would have to edit the configuration files by hand and you could possibly lose your changes when doing an update.
    Search for it on Google. I have no experience with the orphan mode. I beleive the version of NTP on pfSense supports it.

  • LAYER 8 Global Moderator

    If there is no outside connection at all?  What are you using pfsense for in the first place - are you just using it as firewall between lan segments.

    Does pfsense have no wan connection to anything?

    Any box can run ntpd – be it windows, bsd, linux, os x, pretty much anything with much more control over the ntpd than pfsense gives.

    But if this is a lab - I would assume pfsense is being used to isolate the lab from the normal network.  Is there no ntpd on the normal network pfsense wan is connected to?  Even if pfsense has no internet access, it has no access to any other network than this lab?

  • Would it be possible to plug a GPS or other clock into the pfSense box to serve as a stable time source?

  • Banned


    Would it be possible to plug a GPS or other clock into the pfSense box to serve as a stable time source?

    Yes, of course, serial NMEA GPS is supported.

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