Apr 9 (edited) • General discussion
All about Networking
Networking-
Network Engineer
A Network Engineer is responsible for designing, installing, managing, and troubleshooting computer networks so that devices can communicate with each other securely and efficiently A LAN is a network that connects devices within a small geographic area such as a home, office, or school.
Key characteristics:
- Covers a small area
- High speed
- Low cost
- Devices are directly connected through switches or WiFi
Example:
Your home WiFi network is a LAN.
A WAN connects multiple LANs over large distances such as cities, states, or countries.
Key characteristics:
- Covers large geographic areas
- Uses an Internet Service Provider (ISP)
- Slower than LAN
Example:
The internet is the largest WAN.
A VPN creates a secure, encrypted connection over a public network.
Key characteristics:
- Encrypts data (makes it unreadable to outsiders)
- Protects against hackers
- Often used on public WiFi or for remote work
Protocols:
- L2TP
- PPTP
Network Ports
A port is a logical communication endpoint on a device. It allows different types of network traffic to be separated.
Think of:
- IP address = building address
- Port = specific door in that building
Important ports to know:
Service
Port
Function
HTTP
80
Web traffic (not secure)
HTTPS
443
Secure web traffic
FTP
20/21
File transfer
SSH
22
Secure remote access
Telnet
23
Remote access (not secure)
DNS
53
Resolves domain names to IP
DHCP
67/68
Assigns IP addresses
IMAP
143
Email retrieval
IMAP SSL
993
Secure email retrieval
RDP
3389
Remote desktop access
Network Devices
A switch connects devices within the same LAN.
Key characteristics:
- Operates at Layer 2 (Data Link layer)
- Uses MAC addresses
- Sends data only to the intended device
- Faster and more efficient than a hub
Router
A router connects different networks together.
Key characteristics:
- Operates at Layer 3 (Network layer)
- Uses IP addresses
- Connects a LAN to a WAN (e.g., home network to the internet
IP Addressing
An IP address uniquely identifies a device on a network.
Examples:
- 192.168.1.1 (private/local network)
- 8.8.8.8 (public IP)
Purpose:
- Allows devices to send and receive data
DNS (Domain Name System)
DNS translates human-readable domain names into IP addresses.
Example:
- google.com → converted to an IP address
Record types:
- IPv4 uses A records
- IPv6 uses AAAA records
DHCP (Dynamic Host Configuration Protocol)
DHCP automatically assigns IP addresses to devices on a network.
Key characteristics:
- Eliminates the need for manual configuration
- Assigns IP address, subnet mask, gateway, and DNS
Ports:
- 67 (server)
- 68 (client)
Firewall Concept
A firewall controls network traffic based on rules.
It evaluates:
- Source IP address
- Destination IP address
- Port number
- Protocol (TCP or UDP)
Function:
- Allows or blocks traffic based on security rules
Summary (How Everything Works Together)
When a user accesses a website:
- The device connects to a LAN
- The router forwards the request to the WAN (internet)
- DNS resolves the domain name into an IP address
- Communication occurs over a specific port (usually 443 for secure websites)
- The firewall checks and allows the traffic
- The requested data is returned to the user
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All about Networking
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