Nmap - Scanning at preset intervals

How to use Nmap to scan your network at preset intervals

Running a single scan will give you a lot of useful information about the devices on your network. It is likely that before long you will want to schedule scanning on an hourly, daily, or weekly basis.

The NmapWin service, installed along with Nmap, allows you to schedule scans.

Setting the Scan Interval

Step 1 Specify a host, or a range of hosts.

You may specify the host range by using an input file.

Step 2 Click the Service tab.

Tick the day boxes to set when you want the scans to take place. You may, for example, choose not to scan at weekends, in which case you would clear the ticks from Saturday and Sunday.

In the boxes below you can specify the time units, minutes, hours, days, weeks or months. A calendar date to start, and a time to start scanning. Use the slider to adjust or type a value directly in the box.

Step 3 Select the Options required.

Auto Start performs the first scan after the Service is Started and at the specified interval.

Immediately will perform the first scan straight away disregarding any interval settings.

Step 4 Click the Set Param button. This saves your changes by writing them to the registry.

To retrieve the current registry setting setting click Get Param button.

Step 5 Click Start Service.

In addition you may want to log the results of your scans.

Step 6 Close the Nmap window.

This is an optional step which allows the service to run without the GUI. You can, of course, use the GUI to perform other scans and leave the service to run in the background.

Note that if a scan is running at a time prearranged for the service, the service will not run for that interval, but will run again at the next available interval.

You may also want to log the output.