The NTP Monitor is used to test the availability and responsiveness of a Network Time Protocol Service.
NTP is a vital part of some networks. Clusters and other parallel processing environments depend on accurate and synchronized time. If these servers become unsynchronized, older applications may behave unpredictably.
The NTP Monitor:
- Opens a connection to the specified NTP server and waits for the Service to respond.
- Considers the test successful if a valid UTC (Universal Time Coordinated) time value is returned within the specified Maximum Test Duration.
- Safely disconnects from the server upon receipt of the UTC time value.
- Considers the test to have failed if the NTP server fails to respond or responds with an error code indicating that the Service is not available.
Use the NTP Monitor to test that:
- A NTP client can open a connection with an NTP server
- The server adheres to the NTP protocol by responding with the correct codes
- The server responds within a required number of seconds
The Test Parameters dialog box is used to specify the parameters that the NTP Monitor will use to open a connection to the NTP server.
IP Address / Domain Name
Specify the location of the NTP server you want to monitor. Both IP Address and Domain Name are valid entries.
Examples of valid Domain names are: www.xyzcompany.com and xyzcompany.com.
An example of a valid IP address is: 10.200.50.6
Note: Entering an IP address will eliminate any variables introduced by performing a lookup on the DNS server. If your network uses a DHCP server to dynamically assign IP addresses, enter an IP address only if it is "reserved"; otherwise, enter a Domain Name.
UDP Port
Specify the Port Number that the NTP server responds on. By default, the standard Port Number used for NTP communication (Port 123) is already entered.
When the Monitor is in an Up state, test results are reported as shown in the example below:
rtt - Round-Trip Time. This value indicates the time it took the test packet to reach the monitored resource and return a response to ipMonitor. Round-trip time is measured in milliseconds (ms).
When the Monitor is in a Warn, Down, or Lost state, the Last Result field indicates the problem encountered. Different Monitor types generate specific Error Codes in accordance with the technical capabilities of the Monitor. Refer to the Error Codes section of this document for details.
For information on settings common to all Monitor types, such as Identification, Timing, Notification Control and Recovery Parameters, refer to General Monitor Settings.
The following error codes are generated by the NTP Monitor. Error codes are displayed in Real-time and Historical Reports. They can also be added to Alerts using Tokens.
| Message | Details |
|---|---|
| Configuration information for this item is missing some required fields | A required element(s) for Monitor connectivity or testing was not supplied to ipMonitor. |
| Unable to connect to the remote device | The specified address to the connection-based Service is unavailable. |
| Could not obtain an IP address for the remote device | The supplied address was not a valid IP address OR the Server Domain Name could not be translated into an IP address. The Server Domain Name may refer to a local machine name, or a fully qualified domain name. |
| The remote device timed out before sending a response | The resource being monitored did not respond within the maximum allowable time. |
For information on other features and concepts related to those discussed in this article, refer to the following ipMonitor resources:
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Last Updated: March 30, 2007 | What did you think of this topic?