Creating a PING (ICMP) monitor

The NS1 monitoring solution allows you to create monitors that track the health and performance of a specified device or endpoint. users can create any of the following monitor types:

• PING
• HTTP/HTTPS
• TCP

Ping monitoring (ICMP/ICMPv6 echo) is a popular technique used to check the availability of network devices. The monitoring system sends anICMP echo packet to a device and waits for a response. Then, the monitor assesses the connection health based on the specified criteria—such as round trip time or percent packet loss.

This article explains the process for setting up a PING monitor and connecting it to answer metadata.

Instructions

Step 1: Create a PING monitor.

1. In the NS1 portal, navigate to the Monitors tab.

2. Click Add a Monitor.

3. Select PING from the drop-down menu in the upper-left corner.
   
   

4. Under Configuration,

   • Enter a Name for the monitor.

   • Optionally, toggle the button next to Monitor Paused in order to active or deactivate the monitor. (Default is disabled, meaning the monitor is active.)

   • Toggle the button next to Notifications On to enable or disable notifications related to this monitor. (Default is enabled, meaning notifications are active.)

   • Select the desired monitoring regions. These are the locations from which the monitoring will be executed.

   • Under Policy, select one of the following from the drop-down menu:

     • Quorum: The host is marked “down” if tests conducted from a majority of the monitoring regions do not pass the “up” conditions.’

     • All: The host is marked “down” if tests conducted from all of the monitoring regions do not pass the “up” conditions.

     • One: The host is marked “down” if tests conducted from a single monitoring region do not pass the “up” conditions.

   • Under Frequency, enter the amount of time (in seconds) between each monitoring test conducted in each region.

   • Under Up Conditions, click Add Condition to define the conditions the hostname must meet in order to be considered “up.”

     First, choose the metric to validate during the test:

     - Round trip time (RTT): The time (in ms) that it takes the ICMP echo packet to go to and return from the tested host.

     - Percent packet loss: Percentage of ICMP echo packets with no response (timed out).

     Next, choose the comparison operator (=, <, >, etc), and the value to compare. You can add multiple “up” conditions, just note that all conditions must be met in order for a test run to consider the host “up.”

   • Optionally, check the box next to Rapid recheck to automate a second verification test before changing the status of a host. Checking this box can help prevent false positives.

5. Under PING Settings,

   • Enter the number of ICMP echo packets to send. The higher number of packets results in more accurate RTT calculation and packet loss statistics.

   • Enter the IP address (IPv4 or IPv6) or fully-qualified domain name of the device you would like to ping.

   • Optionally, enter a value under Time between packets to indicate the time (in milliseconds) between subsequent echo request packets.

   • Optionally, enter a value under Ping timeout to indicate the time (in milliseconds) before a host should be marked as “failed” or “down.” If the RTT is greater than the ping timeout, then that ICMP echo packet is considered as a timeout. This metric influences the percent packet lost “up” condition. For example, if you set the number of packets to four and one of the packets takes longer than the “ping timeout” value indicated, then 25% (1 out of 4) of the packets are considered lost.

   • Optionally, check the both next to Connect over IPv6. If checked, verify that you entered either a fully qualified domain name or IPv6 address.

     NOTEIf you select this option, the monitor will connect exclusively over IPv6.

6. Once complete, click Save Changes.

Step 2: Connect the monitor to an answer using the NS1 Filter Chain.

To complete the setup process, you must connect the monitor to an answer in order to automatically change the “up” metadata to reflect the status of the monitor. That is, when the tested host meets the up conditions, it will change the metadata to up=true. If the tested host does not meet the up conditions, the metadata is automatically changed to up=false.

1. Under Zones, navigate to the record upon which you want to attach the monitor. Then, click into the record to view associated answers.
   
   
2. Click Create Filter Chain.
   
   
3. Select or drag-and-drop the Up filter option (and any other desired filters) to the list of active filters.
   
   
4. Click Save Filter Chain. Now, you can see the Filter Chain configuration to the left of the answer list.
   
   
5. On the left-hand sidebar showing the Filter Chain configuration, click the UP filter to expand that box and reveal filter-specific metadata options.
   
   
6. Click the up: unset metadata label beneath the answer to view the Answer Metadata configuration screen.
   
   
   
   
7. Click the “feed” icon next to the up/down filter setting to reveal a list of available data feeds—including the monitor you created earlier.
   
   
8. Select the PING monitor you created earlier, and click Ok.
   
   
9. Click Save Record to save your changes.
   
   

Now, when the PING monitor detects a failed endpoint, it automatically adjusts the answer metadata to indicate that the endpoint is “down.” As a result, DNS traffic is steered to better-performing endpoints.