Shape NTP traffic



  • Hi,

    I have a stratum 1 NTP server on a 60/60mbit fiber connection, i also use the same line for private use.
    The problem is that when i use a lot of bandwidth privately the external NTP packets get delayed a little bit which shows in the external monitoring.
    Is there a way i can make the NTP packets have the highest priority?

    Have one WAN and one LAN interface.
    I am absolutely new to traffic shaping and the wizards are not that easy for me.
    Maybe someone can help me through it for the first time?



  • The simplest way would be to run NTP in a dedicate queue.

    For example, I put NTP in qGames for my stratum 2 NTP server. The Internet link is symmetrical 30/30 mbps. I use for years HFSC, with 7 queues created by the wizard. My bandwidth allocation is qDefault = qHigh = qGames = qVoIP = 20%, qLow = 10%, qACK = 8%, qP2P = 2%.



  • Sound very interesting.
    How does pfsense see the difference between NTP and other traffic?

    What do i need to fill in the wizard to have a simular setup?



  • @lars_4:

    Sound very interesting.
    How does pfsense see the difference between NTP and other traffic?

    NTP's destination port is 123 UDP and (rarely) TCP.

    @lars_4:

    What do i need to fill in the wizard to have a simular setup?

    Nothing special, just accept the default to finish the wizard then edit the queues and firewall rules using Firewall -> Traffic Shaper -> By Interface and Firewall -> Rules -> Floating (in v.2.0).



  • @dusan:

    NTP's destination port is 123 UDP and (rarely) TCP.

    Does NTP ever use TCP/123 ?

    It doesn't according to the NTP folks:

    "Note that NTP does not use TCP in any form. Also note that NTP requires port 123 for both source and destination ports." – http://www.eecis.udel.edu/~mills/ntp/html/debug.html


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