Network+ Week 7 Domain 3: Network Operations

How Real Networks Are Managed

Up to now, we've learned how networks work.

This week is about how organizations operate, monitor, maintain, and recover networks.

Think of it this way:

  • Weeks 1–6 = Building the network

  • Week 7 = Running the network

This is where IT Administrators, Network Engineers, and SOC Analysts spend much of their time.

Lesson 1: Network Documentation

Why Documentation Matters

Imagine you're hired by a company with:

  • 50 switches

  • 10 routers

  • 500 computers

  • 20 servers

What happens if nobody knows:

  • Which IP addresses are assigned?

  • Which VLANs exist?

  • What ports are connected where?

The network becomes a nightmare.

Types of Documentation

Network Diagram

Shows how devices connect.

Example:

Internet
    |
 pfSense
    |
 Switch
  /   \
Kali  Windows

A diagram helps engineers understand the network quickly.

IP Address Documentation

Example:

Device

IP Address

pfSense

192.168.10.1

Kali

192.168.10.10

Windows

192.168.10.20

Without documentation:

"What IP is the DNS server?"

Nobody knows.

VLAN Documentation

Example:

VLAN

Purpose

10

Workstations

20

Servers

30

Guests

This becomes extremely important in large environments.

Home Lab Application

Create a document containing:

  • VLANs

  • IP ranges

  • Device names

  • Operating systems

  • Switch ports

This is exactly what real organizations do.

Knowledge Check

  1. Why is documentation important?

  2. What information should a network diagram contain?

Lesson 2: Change Management

The Biggest Cause of Outages

Many outages happen because someone changed something.

Example:

Admin changes firewall rule
↓
Internet breaks
↓
Entire company affected

What Is Change Management?

A process used to control changes.

Instead of:

"Let's change it and see what happens."

Organizations follow a procedure.

Typical Change Process

  1. Request change

  2. Review risk

  3. Approve change

  4. Schedule change

  5. Implement change

  6. Verify results

  7. Document outcome

Example

Suppose you want to create VLAN 30 in your lab.

Bad approach:

Create VLAN
Hope it works

Good approach:

Document
Backup pfSense
Implement
Test
Document results

Knowledge Check

  1. Why is change management important?

  2. What should happen before implementing major changes?

Lesson 3: Backups

What Is a Backup?

A backup is a copy of important data.

Examples:

  • Firewall configuration

  • Server files

  • Databases

  • User data

Why Backups Matter

Imagine:

pfSense crashes

Without backup:

Rebuild everything

With backup:

Restore configuration

Much faster.

Types of Backups

Full Backup

Copies everything.

Advantages:

  • Easy restore

Disadvantages:

  • Large storage requirements

Incremental Backup

Copies only changes since last backup.

Advantages:

  • Small

  • Fast

Disadvantages:

  • More complicated restore

Differential Backup

Copies changes since last full backup.

Sits between full and incremental.

Home Lab Application

Back up:

  • pfSense config

  • Splunk config

  • Virtual machines

  • Important notes

Knowledge Check

  1. What is a backup?

  2. Which backup type copies everything?

Lesson 4: Disaster Recovery

What Is a Disaster?

Anything causing major disruption.

Examples:

  • Hardware failure

  • Fire

  • Flood

  • Ransomware

  • Power outage

Disaster Recovery

The plan used to restore operations.

Example:

Server fails
↓
Restore from backup
↓
Operations resume

Important Terms

RTO

Recovery Time Objective

Question:

How quickly must we recover?

Example:

4 hours

Maximum acceptable downtime.

RPO

Recovery Point Objective

Question:

How much data can we lose?

Example:

30 minutes

Maximum acceptable data loss.

Example

Backups occur every hour.

Server crashes.

Worst-case loss:

1 hour

That is the RPO.

Knowledge Check

  1. What is RTO?

  2. What is RPO?

Lesson 5: High Availability

Goal

Prevent downtime.

Single Point of Failure (SPOF)

A device whose failure breaks everything.

Example:

Internet
   |
 Router
   |
 Entire Network

If router dies:

Network dies

Router = SPOF

Redundancy

Add backup devices.

Example:

Internet
   |
Router A
Router B
   |
 Network

If one fails:

The other continues working.

High Availability Benefits

  • Less downtime

  • Better reliability

  • Improved business continuity

Knowledge Check

  1. What is a single point of failure?

  2. What is redundancy?

Lesson 6: Syslog

One of the Most Important Lessons

Every network device creates logs.

Examples:

User logged in
Firewall blocked traffic
VPN connected

These events are recorded.

What Is Syslog?

A standard way for devices to send logs.

Examples:

  • Routers

  • Firewalls

  • Switches

  • Linux servers

Home Lab Example

pfSense
    |
 Syslog
    |
 Splunk

pfSense sends logs.

Splunk collects them.

Why SOC Analysts Love Logs

Logs help answer:

Who logged in?
What happened?
When did it happen?

Knowledge Check

  1. What is Syslog?

  2. Why are logs important?

Lesson 7: SNMP

What Is SNMP?

Simple Network Management Protocol

Used to monitor network devices.

Example

SNMP can tell you:

  • CPU usage

  • Memory usage

  • Interface status

  • Uptime

  • Device health

Real Example

Network engineer asks:

Is Switch 5 overloaded?

SNMP provides the answer.

SNMP Components

Managed Device

The device being monitored.

Example:

Switch
Router
Firewall
SNMP Manager

The monitoring system.

Example:

Monitoring Server
Agent

Software running on the device.

The agent provides information to the manager.

Home Lab Application

Future setup:

Switch
pfSense
Windows
   |
  SNMP
   |
Monitoring System

Knowledge Check

  1. What does SNMP stand for?

  2. What is SNMP used for?

Week 7 Final Quiz

  1. Why is network documentation important?

  2. What should a network diagram show?

  3. What is change management?

  4. Why are backups important?

  5. What is a full backup?

  6. What is disaster recovery?

  7. What does RTO measure?

  8. What does RPO measure?

  9. What is a single point of failure?

  10. What is redundancy?

  11. What is Syslog?

  12. Why are logs important?

  13. What does SNMP stand for?

  14. What is SNMP used for?

  15. In your home lab, what device could send Syslog data to Splunk?

Lab Mission After Week 7

Your goal is to understand this flow:

Kali
Windows
pfSense
Switch
     |
 Logs (Syslog)
     |
   Splunk

This is the beginning of a SOC environment.

Instead of just building networks, you're now learning how organizations:

  • Document them

  • Monitor them

  • Log activity

  • Recover from failures

  • Keep services available

Those are the skills that connect networking to cybersecurity and will help when you start working with SIEMs, incident response, and eventually CySA+.