By default, whenever an outage is discovered, our system will run five confirmation checks from different locations to ensure that this outage is legitimate. You can lower the number of confirmation checks for any of your network services checks. You may want to do this if you would like be alerted for localized network connection failures.
Accounting for AnyCast IP is a good reason to use this feature (read about it in our blog!). If you are monitoring a service which uses an AnyCast IP, it is possible that the confirmation check can actually reach a different POP which is up, thus cancelling a real outage. To prevent this, you can reduce the amount of confirmations checks needed and whitelist the other nodes which you are certain will reach the same POP. This is a very effective way to monitoring AnyCast infrastructure.
Edit the network service check on which you would like to limit the number of confirmation checks and go to the Incident Alerts tab.
On this tab, you will see a Confirmation Checks Needed drop-down. Select however many confirmation checks you would like, and then click Edit Metric to finalize your change. From now on, this network service check will only perform the number of confirmation checks you've specified.
Keep in mind, that this may increase alerts if you lower the number of confirmation checks needed. The reason we have 5 confirmation checks is to ensure we don't send "false alerts".