Get Started with DNS Tracking

The Manager primary contact has the option to automatically set the tracking method to DNS for hosts when a valid DNS hostname is detected. This applies only when scans are launched by DNS hostname.

For new subscriptions, DNS Tracking may be enabled automatically when the Scan by Hostname add-on is enabled. You can enable or disable DNS Tracking from Scans > Setup > DNS Tracking. Your DNS Tracking selection is preserved when modifying an existing subscription and is not automatically re-enabled during subscription updates.

If the Scan by Hostname add-on is not enabled, you can still enable DNS Tracking. When you enable DNS Tracking, the Portal displays a confirmation message and enables the required dependency.

Take these steps to get started:

1) The Manager primary contact can go to Scans > Setup > DNS Tracking.

2) Select the option Enable DNS Tracking for hosts and click Save.

There is another option to track all assets by DNS if valid hostnames are found. This option is available only for Admin. Once Admin enables it, all the assets will be tracked by DNS when valid hostname is detected irrespective of whether the scan is launched by DNS or IP.

DNS Tracking and the Enforce IP Setting

When you scan by DNS hostname, the hostname is resolved to an IP address at scan time. What happens to a newly resolved IP address depends on whether the Enforce IP setting is enabled for your subscription.

When Enforce IP is enabled

Resolved IP addresses that are not already in your subscription are not added automatically. Only hostnames that resolve to IP addresses already in your subscription are processed. No additional licenses are consumed.

When Enforce IP is disabled

If the resolved IP address is not already in your subscription, it is added automatically and tracked by DNS. Your host inventory stays current as the IP addresses behind your hostnames change.

Each IP address added this way consumes a license. If a hostname resolves to a different IP address in each scan, every one of those IP addresses are added to your subscription. Over time, a single hostname can consume multiple licenses.

Choosing a setting for dynamic environments

In environments where the IP addresses behind your hostnames change frequently, such as cloud, DHCP, or load-balanced setups, choose the setting that fits your priority:

Priority	Recommended setting	What to expect
Keep processing hosts after their IP address changes	Enforce IP disabled	Each new IP address consumes a license.
Limit license usage	Enforce IP enabled	Hosts that resolve to an IP address not in your subscription are not processed.

To check or change the Enforce IP setting for your subscription, contact your Technical Account Manager (TAM) or Qualys Support.