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Sites, Network Zones and Subnets

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In this lesson, you will learn:

  • Why the IP plan is the base of Discovery
  • What to record for each zone and subnet
  • SNWR’s seven zones

🔁 Quick look back: Last time: The Discovery Questionnaire: Questions to Ask. You learned the 40 Discovery questions in eight groups, and why each matters.

1 The Problem: Nobody Has One Network List

Ravi has subnets in a diagram. Oliver has London in a spreadsheet. Kenji has AWS in the console. So:

  • Nobody has one complete list.
  • Two lists disagree about the DMZ.
  • Owners aren’t written anywhere.

🎯 The problem: Nobody at SNWR has one network list with owners.

👉 The fix: Build one IP plan: every zone and subnet, with its owner and purpose.

Table of SNWR zones, subnets and owners.
Figure 1. The Clear View IP plan, confirmed by each owner.

2 What to record

  • Zone name and site.
  • Subnet (for example 10.10.10.0/24).
  • Owner who can answer questions.
  • What lives there (servers, network, users).
  • Whether firewalls sit between it and other zones.

Key term: IP plan

The list of all zones and subnets you may scan, with owners.

Key term: Owner

The person who answers for a subnet and approves scans of it.

3 Checking the plan

Two lists disagreeing is normal. Resolve it before it becomes a scan range.

⚠️ Heads up: Never turn a subnet into a scan range until its owner has confirmed it.

4 Project Clear View: How We Implemented It

📍 Situation: Ravi’s diagram and Oliver’s spreadsheet disagreed about the DMZ.

🧭 Decision: Merge everything into one IP plan and get each owner to confirm their rows.

🛠️ Steps we took:

  1. Combined Ravi’s diagram, Oliver’s spreadsheet and Kenji’s AWS details.
  2. Found the DMZ difference: Ravi’s /28 was right.
  3. Added an owner for each zone.
  4. Asked each owner to confirm their rows in writing.

✅ What we verified:

  • All seven zones are confirmed by their owners.
  • The DMZ subnet is 172.16.5.0/28.

📁 Evidence: The Clear View IP plan. It becomes the ranges in Discovery Schedules › IP Ranges, Range Sets and Exclusions.

5 Quick recap

  • The IP plan lists every zone and subnet you may scan.
  • Each subnet needs an owner.
  • Resolve disagreements before they become ranges.
  • Never scan a subnet its owner hasn’t confirmed.

6 Check yourself

Think of your answer first. Then tap to check.

1 What is an IP plan? Show answer

The list of all zones and subnets you may scan, each with an owner.

2 Two lists disagree about a subnet. What do you do? Show answer

Ask the owner to confirm the right one before it becomes a range.

3 Who owns the Mumbai Finance zone? Show answer

Farah Siddiqui, the security lead.

Nice work! SNWR has one confirmed IP plan. 🎉
Next up: Servers and Operating Systems

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