DNS Checks

DNS checks resolve a given hostname down to the IP address returned, and check this address against a list of expected addresses. If the address returned is outside of the list of expected addresses then the check will fail. DNS checks will resolve any CNAME records as part of the resolution of the given hostname to get to the eventual resolved address.

These checks can be useful for monitoring of DNS based load balancing or automatic failover processes that work through automatic updating of DNS records.

Checks for other types of DNS record such as TXT or SOA records are not currently supported.

Adding a DNS Check

As with all checks, DNS checks can be managed through the API or using Terraform. See the relevant documentation for each for adding DNS checks through these. This guide will show how to add a DNS check through the web console.

• Login to Web Console and select Checks from the main menu.
  
  
  
  
• Click Add located towards the top left of the web console.
  
  
• The Create Check window should now show. Definitions for each field can be found below under Configuration Definitions.
  
  
  
  
• Click Show next to Additional Configuration, and then Edit next to Expected Addresses and add any IP addresses the hostname given should resolve to.
  
  
  
  
• Click Close on the Expected Addresses or Additional Configuration windows if still open, and click Save.
  
  
• You should now see confirmation that the Check was successfully created in the bottom right notification area in the web console. If the check was created in the Dashboard then it will shortly appear under the Check Group it was assigned too.
  
  Newly created checks will initially show with as a successful check in colour on the dashboard until it's first run, but will have its status show as either empty or a '-'.

Amending a DNS Check

As with all checks, DNS checks can be managed through the API or using Terraform. See the relevant documentation for each for adding DNS checks through these. This guide will show how to amend a DNS check through the web console.

• Login to Web Console and select Checks from the main menu.
  
  
  
  
• Click Actions next to the Check you want to edit, and then click Edit.
  
  The list of checks shown can be filtered using the search bar to by the checks name, description, hostname or linked Check Group or App Group names.
  
  
• The Edit Check window should now show. Definitions for each field can be found below under Configuration Definitions.
  
  Ensure the Check Type is set to DNS Check.
  
  
  
  
• To change the list of accepted addresses for this check click Show next to Additional Configuration, and then Edit next to Expected Addresses and amend the list as necessary.
  
  
• Click Close on the Expected Addresses or Additional Configuration windows if still open, and click Save.
  
  
• Confirmation the check was successfully updated should be shown in the bottom right notification area of the web console. Any checks in flight will continue to use the previous configuration.

Removing a DNS Check

• Login to Web Console and select Checks from the main menu.
  
  
  
  
• Click Actions next to the Check you want to edit, and then click Remove.
  
  The list of checks shown can be filtered using the search bar to by the checks name, description, hostname or linked Check Group or App Group names.
  
  
• Click Remove on the Remove Check conformation prompt.
  
  
• Confirmation the check was successfully deleted should show in the bottom right notification area of the web console. Checks in flight may still try and complete so could still produce an alert shortly after deletion. All result history of the check will also be removed.

Configuration Definitions

Name	Description
Name	Provide a name to define what this check is monitoring.
Description	Space to provide a longer description of what the check is monitoring.
Check Type	The type of check this is. This should be set to DNS Check.
Check Host / Host Group	The Check Host or Host Group to run this check on.
Hostname	The hostname to lookup as part of this check.
Check Group	The Check Group to assign this check to, which will determine which dashboard it will be shown in.
Enabled	A toggle to enable or disable this check from running.
Maintenance Override	A toggle to manually put the check into maintenance mode. This allows the check to continue running and storing results, but failures will not produce any alerts or notifications, and do not get counted in some reports.
Check Frequency	The minimum frequency in seconds that this check should be run.
Alert Trigger Failure Count	The number of successive failed checks that should occur before an alert or notification is fired.
Result Retention (days)	The number of days that the history of results for this check should be retained for.
Additional Configuration	Additional configuration for this check can be found by clicking Show. This configuration is defined below under Additional Configuration.

Additional Configuration

Name	Description
Expected Addresses	The list of IP addresses that the given hostname should resolve to. If it resolves to an address outside of this list then the check will fail.