Networking Guides

Basic Network Troubleshooting
Introduction

Network issues can stem from various sources. Follow these steps to systematically identify and resolve common network problems.

Step-by-Step Guide
  1. Check physical connections (cables, routers, switches)
  2. Verify IP configuration using ipconfig (Windows) or ifconfig (Linux/Mac)
  3. Test connectivity with ping command
  4. Check DNS resolution with nslookup
  5. Verify firewall settings
  6. Restart network devices if necessary
Example Commands
# Check IP configuration on Windows
C:\> ipconfig /all

# Check IP configuration on Linux/Mac
$ ifconfig
$ ip addr show

# Test connectivity to Google DNS
$ ping 8.8.8.8

# Test DNS resolution
$ nslookup google.com
Setting Up a VPN Connection
What is a VPN?

A Virtual Private Network (VPN) extends a private network across a public network, enabling users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.

Configuration Steps
  1. Obtain VPN configuration details from your network administrator
  2. Set up VPN connection in your operating system
  3. Configure authentication settings
  4. Test the connection
Windows PowerShell Example
# Add a VPN connection
Add-VpnConnection -Name "CorporateVPN" -ServerAddress "vpn.company.com" -TunnelType "L2TP" -RememberCredential $true

# Connect to VPN
Connect-VpnConnection -Name "CorporateVPN"

Security Best Practices

Password Policy Implementation
Importance of Strong Passwords

Weak passwords are a primary attack vector for security breaches. Implementing a strong password policy is crucial for organizational security.

Recommended Password Policy
  • Minimum length: 12 characters
  • Require uppercase and lowercase letters
  • Require numbers and special characters
  • Password expiration: 90 days
  • Prevent password reuse (last 5 passwords)
  • Account lockout after 5 failed attempts
Example: Windows Group Policy Configuration
# Configure password policy via PowerShell
Set-ADDefaultDomainPasswordPolicy -Identity domain.com -MinPasswordLength 12 -PasswordHistoryCount 5 -MaxPasswordAge 90.00:00:00 -ComplexityEnabled $true
Phishing Awareness
Identifying Phishing Attempts

Phishing is a cybercrime in which targets are contacted by email, telephone, or text message by someone posing as a legitimate institution to lure individuals into providing sensitive data.

Common Indicators of Phishing
Indicator Description Example
Urgent language Creates sense of urgency to bypass rational thinking "Your account will be closed in 24 hours unless..."
Suspicious sender Email address doesn't match the organization support@paypal-security.com (instead of @paypal.com)
Poor grammar Spelling mistakes and awkward phrasing "Dear costumer, your account has been compromise"
Suspicious links Hover over link to see actual URL destination Link text says "www.paypal.com" but goes to different URL
Unexpected attachments Unexpected files, especially executables Invoice.zip or Document.exe

Development Resources

Git Version Control
Introduction to Git

Git is a distributed version control system that allows multiple developers to work on the same project without interfering with each other.

Basic Git Workflow
  1. Initialize repository: git init
  2. Add files to staging: git add <filename>
  3. Commit changes: git commit -m "Commit message"
  4. Push to remote: git push origin <branch>
Common Git Commands
# Clone a repository
git clone https://github.com/user/repository.git

# Create a new branch
git branch new-feature

# Switch to branch
git checkout new-feature

# Merge branches
git checkout main
git merge new-feature

# Check status of files
git status
API Development Best Practices
REST API Design Principles

REST (Representational State Transfer) is an architectural style for designing networked applications.

Key Principles
  • Use HTTP methods explicitly
  • Use nouns instead of verbs in endpoint paths
  • Return appropriate HTTP status codes
  • Version your API
  • Provide filtering, sorting, and pagination
  • Handle errors gracefully
Example API Endpoints
# Get all users
GET /api/v1/users

# Get specific user
GET /api/v1/users/123

# Create new user
POST /api/v1/users
Content-Type: application/json
{
  "name": "John Doe",
  "email": "john@example.com"
}

# Update user
PUT /api/v1/users/123
Content-Type: application/json
{
  "name": "John Smith",
  "email": "john.smith@example.com"
}

# Delete user
DELETE /api/v1/users/123