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IP Ranges, Range Sets and Exclusions

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In this lesson, you will learn:

  • Ranges, range sets and exclusions
  • How to build them from the IP plan
  • How to check exclusions work

🔁 Quick look back: Last time: Process Classifiers for Applications. You learned how process classifiers find applications on a server.

1 The Problem: The Exclusion List Isn’t in ServiceNow Yet

Farah signed the exclusion list. But it lives in a document. If a schedule scans 10.10.0.0/16:

  • It includes 10.10.30.0/24, the building systems.
  • Nothing in ServiceNow stops it.

🎯 The problem: The exclusion list isn’t in ServiceNow yet.

👉 The fix: Build ranges from the IP plan, and add exclusions to every range set that could reach them.

Table of the Mumbai range set.
Figure 1. The SNWR Mumbai Servers range set.

2 Ranges and range sets

Key term: IP range

A list, block or network of addresses to scan.

Key term: Range set

A named group of ranges that a schedule uses.

Key term: Exclusion

An address or range the schedule must skip.

💡 Good to know: Name range sets after the zone, like SNWR Mumbai Servers, so anyone can see what they cover.

3 Checking exclusions

  1. Add exclusions to the range set.
  2. Run the schedule in a test.
  3. Check the results: no excluded address should appear.

4 Project Clear View: How We Implemented It

📍 Situation: Exclusions lived only in a signed document.

🧭 Decision: Build the range sets and add every exclusion.

🛠️ Steps we took:

  1. Created range sets for each zone from the IP plan.
  2. Added the three exclusions to the Mumbai range set.
  3. Ran a test scan on snwrtest.
  4. Checked no excluded address was touched.

✅ What we verified:

  • No excluded address appears in results.
  • Farah reviewed the range sets.

📁 Evidence: Range sets on snwrdev and snwrtest. Exclusions are tested again as AC-09 in Quality Assurance.

5 Quick recap

  • Ranges list addresses. Range sets group them.
  • Exclusions skip addresses that must never be scanned.
  • Name range sets after zones.
  • Test that excluded addresses never appear.

6 Check yourself

Think of your answer first. Then tap to check.

1 What is a range set? Show answer

A named group of ranges that a schedule uses.

2 Which Mumbai addresses are excluded? Show answer

10.10.10.250, 10.10.30.0/24 and 10.10.20.0/22.

3 How do you prove an exclusion works? Show answer

Run a test scan and check no excluded address appears in the results.

Nice work! SNWR’s no-go areas are enforced in ServiceNow. 🎉
Next up: Creating a Discovery Schedule

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