NTP monitor

Hi Jai, please see below the VS and pool config. The current set up is : traffic to two NTP servers load-balanced (source address persistent) by F5 ( IOS 12.1). Problem is, current VS set up monitoring udp 123 port. Its not checking if the ntp server actually lost the sync (stratum greater than 1 o 0). So I want to set up an external monitor, which will monitor whether NTP server on stratum 1, if it loses the stratum 1, then make it forced offline, and when it restored make it enabled again.. In addition to that, if the external monitor could see both NTP Servers lost sync at given time, then switch to default udp_123 monitoring. As we don't want to lose NTP server all together.

 ltm virtual cus-ntp-01 {

  destination 21.12.63.252:ntp

  ip-protocol udp

  mask 255.255.255.255

  persist {

    source_addr {

      default yes

    }

  }

  pool cus-ntp

  profiles {

    udp { }

  }

  source 0.0.0.0/0

  translate-address enabled

  translate-port enabled

  vs-index 26

}

ltm pool cus-ntp {

  allow-snat no

  members {

    2.10.91.61.6:ntp {

      address 2.10.61.6

      session monitor-enabled

      state up

    }

    2.10.61.7:ntp {

      address 2.10.61.7

      priority-group 2

      session monitor-enabled

      state up

    }

  }

  min-active-members 1

  monitor min 1 of { udp_123 }

}