How to run a full network discovery with OpenNMS

With OpenNMS up and running, you now need to have it discover all of your network assets. Find out how.

How to run a full network discovery with OpenNMS With OpenNMS up and running, you now need to have it discover all of your network assets. Find out how.

OpenNMS is an open source network monitoring and managing tool, that is sure to please any admin. It's powerful, it's flexible, and with your ever-growing network responsibilities, it should be considered a necessity.

Once you have OpenNMS up and running (see "How to install OpenNMS network manager on Ubuntu 18.04"), one of your first tasks will be to have it run a full network discovery. If you don't opt to go the full network discovery route, you'll have to manually enter each asset by IP address. That is in no way an efficient means of making OpenNMS aware of your network-attached devices. But how do you run a full network discovery? I'm going to show you.

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What you'll need

The only things you'll need to make this happen are a working instance of OpenNMS and assets to be discovered on your network. With those things at the ready, let's discover.

How to configure the discovery with OpenNMS

The easiest method of locating assets on your network is to ping every possible IP address via the OpenNMS Discovery Daemon. To set this up, first log in to your OpenNMS dashboard as an admin user. Once on the Dashboard, click the Admin drop-down and select Configure OpenNMS (Figure A).

Figure A

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The Admin drop-down.

From the Configuration window, click Configure Discovery, under Provisioning (Figure B).

Figure B

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The Configuration setting we're looking for.

From within the Configure Discovery window, click Add New in the Include Ranges section. In the resulting popup window (Figure C), type the lowest range of your IP address scheme (such as 192.168.1.0) in the Begin IP Address section and the highest range of your IP address scheme (such as 192.168.1.220) in the End IP Address section. Click Add to save the range.

Figure C

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Adding our discovery range for OpenNMS.

Once you've saved the range, click the Save And Restart Discover button at the top of the Discovery page. OpenNMS will automatically begin locating assets on your network. It should take about five minutes for the discovery to complete, depending on how many devices are on your network. After you've given it time to run, click the Info drop-down (at the top of the OpenNMS page) and click Nodes. You should now see a listing of devices OpenNMS has discovered (Figure D).

Figure D

opennmsdiscoveryd.jpg

Our discovered devices.

Click on any one of those nodes to view and/or manage it.

Congratulations, OpenNMS is now aware of every available asset on your network. You don't have to enter them manually, one at a time. Enjoy managing your devices with this powerful open source network management tool.

Also see

Business network concept. SaaS(Software as a Service).

Image: iStockphoto/metamorworks