Chapter 2: Networking (Core 1 – 220-1201)
2.1 Networking Fundamentals
Networking allows devices to communicate and share resources such as internet access, files, and printers.
Types of Networks
|
Type |
Description |
|
LAN (Local Area Network) |
Small area (home, office) |
|
WAN (Wide Area Network) |
Large geographic area (internet) |
|
PAN (Personal Area Network) |
Very small (Bluetooth devices) |
|
MAN (Metropolitan Area Network) |
City-wide network |
Network Topologies
|
Topology |
Description |
|
Star |
Devices connect to central switch/router |
|
Mesh |
Devices connect to each other (high redundancy) |
|
Bus |
Single backbone cable |
|
Ring |
Circular connection |
Star topology is most common today
2.2 IP Addressing
IPv4 Addressing
- Format: 192.168.1.1
- 32-bit address
- Divided into:
- Network portion
- Host portion
Private IP Ranges (MEMORIZE)
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
Public vs Private IP
|
Type |
Description |
|
Public |
Internet-routable |
|
Private |
Internal network only |
IPv6 Addressing
- 128-bit address
- Example: 2001:0db8:85a3::8a2e:0370:7334
- Benefits:
- More addresses
- Improved efficiency
Subnet Mask
Defines network vs host portion.
Example:
- IP: 192.168.1.10
- Mask: 255.255.255.0
DHCP (Dynamic Host Configuration Protocol)
- Automatically assigns IP addresses
- Provides:
- IP address
- Subnet mask
- Default gateway
- DNS server
DNS (Domain Name System)
- Converts domain names → IP addresses
Example: google.com → 8.8.8.8
2.3 Ports & Protocols (HIGH PRIORITY)
Common Ports (MEMORIZE)
|
Protocol |
Port |
Purpose |
|
HTTP |
80 |
Web (unsecured) |
|
HTTPS |
443 |
Secure web |
|
FTP |
21 |
File transfer |
|
SSH |
22 |
Secure remote login |
|
Telnet |
23 |
Unsecure remote login |
|
SMTP |
25 |
Email sending |
|
DNS |
53 |
Name resolution |
|
DHCP |
67/68 |
IP assignment |
|
RDP |
3389 |
Remote desktop |
Protocol Types
- TCP
- Reliable
- Connection-oriented
- UDP
- Faster
- Connectionless
2.4 Network Devices
Core Devices
|
Device |
Function |
|
Router |
Connects networks |
|
Switch |
Connects devices in LAN |
|
Hub |
Broadcasts data (outdated) |
|
Modem |
Converts ISP signal |
|
Access Point (AP) |
Provides Wi-Fi |
Firewall
- Filters traffic based on rules
- Protects network
2.5 Wireless Networking
Wi-Fi Standards
|
Standard |
Speed |
Frequency |
|
802.11n |
Medium |
2.4/5 GHz |
|
802.11ac (Wi-Fi 5) |
Fast |
5 GHz |
|
802.11ax (Wi-Fi 6) |
Faster |
2.4/5 GHz |
Frequencies
|
Band |
Pros |
Cons |
|
2.4 GHz |
Longer range |
Slower |
|
5 GHz |
Faster |
Shorter range |
Wireless Security
|
Type |
Security Level |
|
WEP |
Weak ❌ |
|
WPA |
Better |
|
WPA2 |
Strong ✅ |
|
WPA3 |
Strongest ✅ |
2.6 Network Cables & Connectors
Cable Types
|
Type |
Use |
|
Twisted Pair (Ethernet) |
LAN connections |
|
Coaxial |
Cable internet |
|
Fiber Optic |
High-speed, long distance |
Ethernet Categories
|
Type |
Speed |
|
Cat5e |
1 Gbps |
|
Cat6 |
10 Gbps |
|
Cat6a |
Higher performance |
Connectors
- RJ-45 → Ethernet
- RJ-11 → Telephone
2.7 Network Configuration Tools
Windows Commands (MEMORIZE)
|
Command |
Purpose |
|
ipconfig |
View IP config |
|
ping |
Test connectivity |
|
tracert |
Trace route |
|
nslookup |
DNS lookup |
|
netstat |
Network stats |
2.8 Network Troubleshooting
Troubleshooting Methodology
- Identify problem
- Establish theory
- Test theory
- Implement fix
- Verify
- Document
Common Issues
No Internet Access
Causes:
- Wrong IP
- DNS failure
- Gateway issue
Fix:
- Run ipconfig
- Renew IP (ipconfig /renew)
- Check DNS
Slow Network
Causes:
- Interference
- Bandwidth congestion
Fix:
- Switch to 5 GHz
- Move closer to router
Weak Wi-Fi Signal
Causes:
- Distance
- Obstacles
Fix:
- Reposition router
- Add extender
No Network Connection
Causes:
- Bad cable
- Disabled NIC
Fix:
- Replace cable
- Enable adapter
2.9 Virtualization & Networking Basics
Virtual Networking Modes
- NAT → Internet sharing
- Bridged → Appears as real device
- Internal → Isolated network
Use Cases
- Testing networks
- Simulating environments
- Troubleshooting practice
2.10 Exam Tips (CRITICAL)
✔ Memorize port numbers
✔ Know IP ranges (private vs public)
✔ Understand TCP vs UDP
✔ Know network devices and roles
✔ Practice troubleshooting scenarios
Quick Knowledge Check
- What port does HTTPS use?
A. 80
B. 443
C. 21
D. 22 - Which device connects networks?
A. Switch
B. Router
C. Hub
D. NIC - Which IP range is private?
A. 8.8.8.8
B. 192.168.1.1
C. 172.50.1.1
D. 1.1.1.1 - Which protocol is connectionless?
A. TCP
B. UDP
C. HTTP
D. FTP - What command tests connectivity?
A. ipconfig
B. netstat
C. ping
D. tracert
Answers: 1-B, 2-B, 3-B, 4-B, 5-C