Welcome to DNS Filtering, a powerful tool that helps protect your organization from online threats.

This guide is for beginners in cybersecurity looking to use DNS Filtering in Nebula. We will guide you through creating your first DNS rule with the default categories to block harmful websites.

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Step 1 - Check system requirements

Before beginning, make sure the devices meet the system requirements for DNS Filtering.

  1. In Nebula, go to Manage Endpoints.
  2. Check the OS release name column. If the column is missing, click Add / Remove columns at the top right and select it.
  3. Verify devices run a supported OS from this list. DNS Filtering won’t work on an unsupported OS.

Step 2 - Start creating the DNS rule

A DNS rule enforces security policies by determining which websites are allowed and blocked on the devices.

If your company uses a private domain server, add it to the global exclusions before creating a DNS rule. See Add Global Exclusions for DNS Filtering.

Let’s begin creating your first DNS rule to protect your network.

  1. Go to Monitor DNS Filtering.
  2. Click Rules Add DNS Rule.

Step 3 - Enter a rule name and select policies

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Follow these steps on the rule details screen:

  1. Enter a Rule name: Enter “Basic DNS Rule”
  2. Select Policies: Endpoints are assigned to a single policy based on their Nebula group. Select which Nebula policies this DNS rule applies to. If you want the rule to apply to every endpoint, select all policies.
  3. Add a Description (optional): Provide context or notes for future reference.
  4. Click Next to continue.

Step 4 - Save the Block list

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The block list determines which websites are blocked. We’ve pre-selected security categories to prevent threats like malware and phishing using the Basic Protection template.

For stricter filtering, select a different template to quickly add categories, and choose additional categories if needed:

  1. Use a template to quickly apply a set of recommended content categories. Click Preview to see which categories are included in each template, and click Apply to add them to the block list.
  2. To block more content, select specific Content categories using the drop-down menu. Popular options include:
    1. Adult Themes
    2. Gambling
    3. Children’s Internet Protection Act (CIPA)
  3. Keep the current security categories selected.
  4. Click Next to proceed.

Step 5 - Save the Allow list

The allow list controls which websites devices can access. If a site is on both the allow and block lists, the allow list takes priority over the block list.

For example, if Social Networks are blocked but a company has a Facebook page to manage, facebook.com needs to be added to the allow list.

  1. Leave the allow list blank for now. It can be updated later.
  2. Click Next.

Step 6 - Review and save DNS rule

This last screen lets you review and save the DNS rule. Once saved, a plugin that filters network traffic is installed on all endpoints in the selected policies.

Steps for macOS devices: Before you save, please be aware that Mac users are prompted to approve a system extension and a certificate as soon as you save the DNS rule.

  • If the device user is an admin on their Mac, share this PDF guide with them so they can follow the steps to approve.
  • If not, then you’ll need to review the PDF and complete the steps for them.
  1. Review your selections.
  2. Click Save Rule.

Still have questions?

Support is available via chat, phone or by creating a ticket. You can also use our virtual assistant for guided assistance.

Learn more