Network Time Protocol Setup

Authentication for the Controller and NTP/SNTP Server

We highly recommend that controllers synchronize their time with an external NTP/SNTP server. We also recommend that you authenticate this connection to the NTP/SNTP server, as a best practice. By default, an MD5 checksum is used in this scenario.

Each NTP/SNTP server IP address is added to the controller database. The respective controller then attempts to poll an NTP/SNTP server from this database in the index order. The controller then obtains and synchronizes the current time at each user-defined polling interval, as well as following a reboot event. By default, the NTP polling interval is 600 seconds.

Guidelines and Restrictions on NTP

  • When the time difference between the NTP server and the controller exceeds 1000s, the ntpd process exits and adds a panic message to the system log. In this situation, set the time on the controller manually.

  • As a part of the federal certification requirements, controller supports NTPv4 protocol which is a standard Open Source Code.

  • Controllers support both the versions—NTPv3 and NTPv4 versions. However you can use either one of the two versions and not both at the same time.

  • NTPv4 supports both IPv4 and IPv6 servers, and supports SHA1 authentication for NTP messages.

Configuring the NTP/SNTP Server to Obtain the Date and Time (GUI)

Procedure

Step 1

Choose Controller > NTP > Server to open the NTP Severs page.

Step 2

From the NTP Version drop-down list, choose 4.

Step 3

Click Apply.

Step 4

Click New to add a new NTP/SNTP Server.

Step 5

(Optional) In the Server Index (Priority) field, enter the NTP/SNTP server index.

The controller tries Index 1 first, then Index 2 through 3, in a descending order. Set this to 1 if your network is using only one NTP/SNTP server.

Step 6

Enter the server IP address.

You can enter an IPv4 or an IPv6 address or a fully qualified domain name (FQDN), which should meet the following criteria:

  • Contains only a-z , A-Z, and 0-9 characters.

  • Does not start with a dot (.) or a hyphen (-).

  • Does not end with a dot (.).

  • Does not have 2 consecutive dots (..).
Step 7

Enable or disable the NTP/SNTP Authentication.

Step 8

If you enable the NTP/SNTP Authentication, enter the Key Index.

Step 9

Click Apply.

Step 10

Delete an existing NTP server IP address or DNS server by hovering the cursor over the blue drop-down arrow for that server index and choose Remove.

Step 11

Confirm the deletion by clicking on OK in the dialog box.

Configuring the NTP/SNTP Server to Obtain the Date and Time (CLI)

Use these commands to configure an NTP/SNTP server to obtain the date and time:

Procedure

  • To specify the NTP/SNTP server for the controller, enter this command:

    config time ntp server index ip-address

  • (Optional) To specify the polling interval (in seconds), enter this command:

    config time ntp interval

  • To enable or disable NTP/SNTP server authentication, enter these commands:

    • config time ntp auth enable server-index key-index —Enables NTP/SNTP authentication on a given NTP/SNTP server.

    • config time ntp key-auth add key-index md5 {ascii | hex} key—Adds an authentication key. By default MD5 is used. The key format can be ASCII or hexadecimal.

    • config time ntp key-auth delete key-index —Deletes authentication keys.

    • config time ntp auth disable server-index —Disables NTP/SNTP authentication.

    • show ntp-keys —Displays the NTP/SNTP authentication related parameter.

  • To delete an NTP server IP address or DNS server from the controller, enter this command:

    config time ntp delete NTP_server index

  • Configure the NTP version by entering this command:

    config time ntp version version

    Note
    When the NTP version changes, the configured servers are deleted.

  • Configuring the NTP polling interval when using NTP version 4 by entering this command:

    config time ntp pollinterval maxpoll minpoll server-index

Configuring NTPv4 Keys for Authentication (GUI)

Procedure

Step 1

Choose Controller > NTP > Keys to open the NTP Key page.

Step 2

Click New to add a new NTP key.

Step 3

Enter the Key Index number in the Key Index field.

Step 4

From the Checksum drop-down list, choose SHA1.

Step 5

From the Key Format drop-down list, choose ASCII.

Step 6

Enter the Key in the Key field.

Step 7

Click Apply.