DNS Health Check Settings

The available set of DNS health check settings can be viewed in the illustration below.

The following table describes the various options that can be defined.

Option Description

Health Check Type

Determines the type of health check that will be performed. The available options are:

  • HTTP/HTTPS: Use these health check types to query a web server using a GET or POST request over port 80 and 443, respectively.
  • TCP/TCP SSL: Use these health check types to establish a TCP connection to other services, such as FTP, SMTP, POP3, IMAP, etc.).

Method Type

HTTP or HTTPS Health Checks Only

Determines whether a GET or a POST request will be used to poll health status.

Requests used to poll servers will not include a request body.

URI

HTTP or HTTPS Health Checks Only

Determines the URI for the GET/POST request that our health check agents will use to poll health status. The URI's protocol (i.e., http:// or https://) was specified in the Health Check Type option and therefore should not be included in this option.

Do not specify a CDN or edge CNAME URL, since these URLs resolve to our network and are therefore unsupported. However, you may configure a health check to point directly to your web servers.
Learn more about CDN and edge CNAME URLs.

IP Version

HTTP or HTTPS Health Checks Only

Determines whether the HTTP/HTTPS request should be performed using IPv4 or IPv6.

Ipv4 or IPv6

TCP or TCP SSL Health Checks Only

Defines the IPv4 or IPv6 IP address to which the TCP request will be directed.

Do not specify an IP address for a web server within our network (i.e., CDN).

Port Number

TCP or TCP SSL Health Checks Only

Determines the port over which the request will be performed. Make sure that monitored server(s) allow communication over this port.

Content Verification

Defines the set of ASCII characters through which a server's health will be verified. Our health check agents will look for the specified text in the body of the server’s response to a health check request.

If this option is left blank, then our servers will simply verify the following:

  • HTTP: The HTTP status code for the response is a 200 OK.
  • TCP: A connection could be established.

Seconds Between Checks

Determines the time interval, in seconds, between polling requests sent by our health check agents to monitored server(s).

Email Notification

Determines the email address to which a notification will be sent whenever there is a change in the health state of the server/domain associated with this health check configuration.

Number of failed Checks

Each health check agent will attempt to communicate with a monitored server/domain to check whether it can pass a health check. A health check agent will record the results of each attempt (i.e., pass or fail), but it cannot make an assessment on health state until the same result occurs consecutively the number of times specified in this option.

Although each health check agent keeps track of whether a server/domain has passed/failed health checks, a majority consensus of all health check agents is required to change its health state.

Reintegration Method

Our DNS service will stop distributing traffic to a server/domain that has failed a majority of health checks. This option determines the process through which a server/domain can be reintegrated into a load balancing or failover group.

Set this option to one of the following:

  • Automatic: Indicates that our health check agents will continue to poll a server/domain that has failed a majority of health checks. Once it is deemed healthy by a majority of our health check agents, it will automatically be reintegrated into a load balancing or failover configuration. The Number of failed Checks option determines the number of successful validations required before it can be considered healthy.
  • Manual: Indicates that manual intervention is required to reintegrate a server/domain into a load balancing or failover group. Learn how to manually reintegrate a server/domain in a load balancing or failover group.