Create a Host Discovery Scan
Knowing what hosts are on your network is the first step to any vulnerability assessment. Launch a host discovery scan to see what hosts are on your network (and associated information such as IP address, FQDN, operating systems, and open ports, if available). After you have a list of hosts, you can choose what hosts you want to target in a specific vulnerability scan.
Note: Hosts discovered by a host discovery scan do not count towards your license limit, if applicable. For more information, see License Utilization.
The following overview describes a typical workflow of creating and launching a host discovery scan, then creating a follow-up scan that target-discovered hosts that you choose. In Tenable Nessus Essentials and Tenable Nessus Professional trials, a wizard walks you through a simplified version of this process. You can always manually launch a host discovery scan or follow-up scan using the workflow outlined in this overview.
Create and launch a host discovery scan
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In the top navigation bar, click Scans.
The My Scans page appears.
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In the upper right corner, click the New Scan button.
The Scan Templates page appears.
- Under Discovery, click the Host Discovery template.
- Configure the host discovery scan:
- For Name, enter a name for the scan.
For Targets, enter targets as hostnames, IPv4 addresses, or IPv6 addresses.
Tip: For IP addresses, you can use CIDR notation (for example, 192.168.0.0/24), a range (for example, 192.168.0.1-192.168.0.255), or a comma-separated list (for example, 192.168.0.0,192.168.0.1). For more information, see Scan Targets.
- (Optional) Configure the remaining settings.
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To launch the scan immediately, click the 
button, and then click Launch.
Tenable Nessus runs the host discovery scan, and the My Scans page appears.
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In the scans table, click the row of a completed host discovery scan.
The scan's results page appears.
- In the Hosts tab, view the hosts that Tenable Nessus discovered, and any available associated information, such as IP address, FQDN, operating system, and open ports.
Create and launch a scan on one or more discovered hosts
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In the top navigation bar, click Scans.
The My Scans page appears.
- In the scans table, click the row of your completed host discovery scan.
The scan's results page appears.
- Click the Hosts tab.
Tenable Nessus displays a table of scanned hosts.
- Select the check box next to each host you want to scan in your new scan.
At the top of the page, the More button appears.
- Click the More button.
A drop-down box appears.
- Click Create Scan.
The Scan Templates page appears.
- Select a scan template for your new scan.
Tenable Nessus automatically populates the Targets list with the hosts you previously selected.
- Configure the rest of the scan settings, as described in Scan and Policy Settings.
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To launch the scan immediately, click the button, and then click Launch.
Tenable Nessus saves and launches the scan.