ExtremeSwitching (EXOS)

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Configure NTP source ip

  • 1.  Configure NTP source ip

    Posted 07-09-2015 02:06
    I am running EXOS 15.7.1 on an X670-G2 and im trying to configure NTP.
    the ntp server is a few hops away and the connection from the switch to next router is using a point to point /30 vlan.
    when it sends an ntp request it uses the source ip of the /30 point to point vlan, but i need it to use a different self ip.
    is anyway to configure what ip to use to when sending ntp requests?



  • 2.  RE: Configure NTP source ip

    Posted 07-09-2015 04:47
    Hi,

    There isn't a feature to specify the source VLAN to carry the NTP request.


  • 3.  RE: Configure NTP source ip

    Posted 07-09-2015 07:12
    ok thanks for the info, ill have to work out a way around it.


  • 4.  RE: Configure NTP source ip

    Posted 12-09-2015 08:01
    Exactly my problem as well - is there a way to change the source ip-address, e.g. via ACL?


  • 5.  RE: Configure NTP source ip

    Posted 12-09-2015 08:08
    i didnt find a way... i ended up using the p2p ip and had to get the ntp server to allow it.


  • 6.  RE: Configure NTP source ip

    Posted 12-09-2015 09:40
    Thanks for your quick reply!

    I can't do that: The provider is blocking traffic from that IP, as it's for BGP transit only.

    Will let you know when (if) I have a solution...


  • 7.  RE: Configure NTP source ip

    Posted 12-10-2015 07:44
    Just a thought but could you set a static route in the routing table to force it out of a specific interface via next hop?


  • 8.  RE: Configure NTP source ip

    Posted 12-10-2015 07:50
    We are currently thinking of something similar. If I do just that, it will be redirected at the next hop back to original router and then routed again to next hop... so it has to be combined with an ACL as well, overwriting the static route in case it comes back.


  • 9.  RE: Configure NTP source ip

    Posted 12-10-2015 07:52
    ...or static routes/PBR all along the path.


  • 10.  RE: Configure NTP source ip

    Posted 01-18-2019 09:10
    I have the similar situation.

    I have a p2p / 30 net and mgmt network without NAT and several SVIs that are connected to the Internet(NAT). In this case, my NTP does not work, because the switch sends packets through these networks(/30 or mgmt) without NAT. Is there a simple way to configure the source IP for NTP after 3 years? (XOS 16.2.5.4 for G1 or XOS 21.1.5.2 for G2)