Network Time Protocol (NTP) time synchronization

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The IBM i integrated time-based one-time password (TOTP) implementation requires the server time be in synchronization with client authenticator devices.

Minor time-drift is tolerated by the TOTP algorithm. However using the Network Time Protocol (NTP) client is recommended to keep the server and device clocks synchronized. For more information, refer to Simple Network Time Protocol.

Configuring the NTP client

  • Check the QTIMADJ system value.
    • If it is set to QIBM_OS400_NTP, then the NTP client is running.
    • If it is set to *NONE, then the NTP client is not running. Start NTP services using command: STRTCPSVR SERVER(*NTP).
    • If it is set to QIBM_OS400_SNTP, then the SNTP client is running instead of NTP. Change the client type by following these steps:
      1. In IBM Navigator for i, select Network > Servers > TCP/IP Servers.
      2. Right click on SNTP and select Stop.
      3. Right click SNTP and select Properties.
      4. Set the client to auto-start when TCP/IP is started.
      5. Click on the Client tab and specify client type NTP.
      6. Add multiple time servers reachable on your network.
      7. Click OK to save the changes.
      8. Right click on SNTP and select Start.
    • For more information about the QTIMADJ system value, refer to Specifying SNTP as your time maintenance application.
  • For additional NTP client troubleshooting concepts, refer to Troubleshooting SNTP application.