🔧 Types of IT Problems & Real-time Solutions
🖥️ Hardware Issues
Common Problems: Computer won't start, overheating, blue screen, peripheral failures
Real-time Solutions:
- Check power connections and cables
- Run hardware diagnostics
- Check RAM seating and connections
- Monitor system temperatures
- Replace faulty components
💻 Software Issues
Common Problems: Application crashes, slow performance, compatibility issues, installation failures
Real-time Solutions:
- Restart applications and services
- Update software to latest versions
- Check system requirements
- Run system file checker (sfc /scannow)
- Reinstall problematic applications
🌐 Network Issues
Common Problems: No internet connection, slow speeds, DNS issues, VPN problems
Real-time Solutions:
- Check cable connections
- Restart network equipment
- Flush DNS cache (ipconfig /flushdns)
- Update network drivers
- Test with different devices
🔐 Security Issues
Common Problems: Malware infections, suspicious activities, account lockouts
Real-time Solutions:
- Run full system antivirus scan
- Check system logs for anomalies
- Reset passwords and enable 2FA
- Isolate affected systems
- Apply security patches
⌨️ Essential Shell Commands
🪟 Windows Commands
System Information & Diagnostics
systeminfo # System information
msinfo32 # System information GUI
dxdiag # DirectX diagnostics
sfc /scannow # System file checker
chkdsk C: /f # Check disk for errors
Network Troubleshooting
ipconfig /all # Network configuration
ipconfig /flushdns # Flush DNS cache
ipconfig /release # Release IP address
ipconfig /renew # Renew IP address
ping google.com # Test connectivity
nslookup google.com # DNS lookup
tracert google.com # Trace route
netstat -an # Network connections
Process & Service Management
tasklist # List running processes
taskkill /im notepad.exe # Kill process by name
taskkill /pid 1234 # Kill process by PID
services.msc # Services management
sc query # Service status
sc start service_name # Start service
sc stop service_name # Stop service
🐧 Linux Commands
System Information
uname -a # System information
lscpu # CPU information
free -h # Memory usage
df -h # Disk usage
lsblk # Block devices
dmesg # System messages
Process Management
ps aux # List processes
top # Process monitor
htop # Enhanced process monitor
kill -9 1234 # Kill process by PID
killall firefox # Kill process by name
jobs # List background jobs
nohup command & # Run command in background
Network & Security
ifconfig # Network interface configuration
ip addr show # Show IP addresses
netstat -tulpn # Network connections
ss -tulpn # Socket statistics
iptables -L # Firewall rules
sudo ufw status # UFW firewall status
🏢 Active Directory Management
Opening Active Directory Tools
Windows Server:
# Open Active Directory Users and Computers
dsa.msc
# Open Active Directory Sites and Services
dssite.msc
# Open Active Directory Domains and Trusts
domain.msc
# Open Group Policy Management
gpmc.msc
PowerShell AD Commands
# Import Active Directory module
Import-Module ActiveDirectory
# Get user information
Get-ADUser -Identity "username" -Properties *
# Create new user
New-ADUser -Name "John Doe" -SamAccountName "jdoe" -UserPrincipalName "jdoe@domain.com"
# Reset user password
Set-ADAccountPassword -Identity "jdoe" -Reset -NewPassword (ConvertTo-SecureString "NewPassword123!" -AsPlainText -Force)
# Add user to group
Add-ADGroupMember -Identity "IT_Team" -Members "jdoe"
# Get computer information
Get-ADComputer -Identity "COMPUTER01" -Properties *
Linking Windows Systems to AD
Steps to join Windows to Domain:
- Configure DNS to point to Domain Controller
- Go to System Properties → Change Settings
- Click "Change" and select "Domain"
- Enter domain name and provide credentials
- Restart computer
# PowerShell method to join domain
Add-Computer -DomainName "yourdomain.com" -Credential (Get-Credential) -Restart
Linking Linux Systems to AD
Using Realmd (RHEL/CentOS):
# Install required packages
sudo yum install realmd sssd oddjob oddjob-mkhomedir
# Discover domain
sudo realm discover yourdomain.com
# Join domain
sudo realm join yourdomain.com
# Verify join
sudo realm list
Using Winbind (Ubuntu):
# Install packages
sudo apt-get install winbind samba-common-bin
# Edit /etc/samba/smb.conf
sudo nano /etc/samba/smb.conf
# Join domain
sudo net ads join -U administrator
# Start services
sudo systemctl enable winbind
sudo systemctl start winbind
🤓 Technical Interview Questions
Q: What is the difference between TCP and UDP?
Answer: TCP is connection-oriented, reliable, and ensures data delivery with error checking. UDP is connectionless, faster, but doesn't guarantee delivery. TCP
is used for web browsing, email; UDP for streaming, gaming.
Q: Explain the OSI model layers.
Answer: 7 layers - Physical, Data Link, Network, Transport, Session, Presentation, Application. Remember: "Please Do Not Throw Sausage Pizza Away"
Q: What is DHCP and how does it work?
Answer: Dynamic Host Configuration Protocol automatically assigns IP addresses to devices. Process: DISCOVER → OFFER → REQUEST → ACK (DORA)
Q: How would you troubleshoot a computer that won't boot?
Answer: Check power supply, cables, RAM seating, boot order in BIOS, hard drive health, run hardware diagnostics, check for POST codes.
Q: What is Active Directory and its components?
Answer: Microsoft directory service for managing network resources. Components: Domain Controllers, Organizational Units, Group Policy, DNS, Sites and Services.
Q: Explain the difference between RAID 0, 1, and 5.
Answer: RAID 0: Striping (performance, no redundancy), RAID 1: Mirroring (redundancy), RAID 5: Striping with parity (performance + redundancy, min 3 drives)
Q: What is DNS and how does name resolution work?
Answer: Domain Name System translates domain names to IP addresses. Process: Local cache → Recursive resolver → Root servers → TLD servers → Authoritative
servers
Q: How do you secure a wireless network?
Answer: Use WPA3 encryption, strong passwords, hide SSID, MAC filtering, regular firmware updates, guest network isolation, monitor for rogue access points.
🧠 Logical Problem-Solving Questions
Q: Users can't access a specific website, but other sites work. How do you troubleshoot?
Approach: Check if it's DNS (try IP), test from different locations, check firewall rules, verify site status, clear browser cache, test different browsers.
Q: Network is slow for all users. What's your troubleshooting approach?
Approach: Check bandwidth utilization, identify heavy users/applications, test different network segments, check switch/router performance, verify ISP
connection.
Q: A server is running out of disk space. How do you handle this?
Approach: Identify large files/logs, clean temporary files, move data to other storage, implement log rotation, add more storage, set up monitoring alerts.
Q: How would you handle a suspected security breach?
Approach: Isolate affected systems, preserve evidence, assess scope, notify stakeholders, change passwords, run security scans, review logs, implement additional
controls.
🗣️ Behavioral Interview Questions
💡 How to Answer Behavioral Questions
Use the STAR Method:
- Situation: Describe the context
- Task: Explain what needed to be done
- Action: Detail what you did
- Result: Share the outcome
Q: Tell me about a time you had to deal with a difficult user.
Focus on: Active listening, empathy, patience, problem-solving, professionalism, follow-up
Q: Describe a challenging technical problem you solved.
Focus on: Problem analysis, research methods, testing approaches, collaboration, documentation, learning outcomes
Q: How do you prioritize multiple urgent requests?
Focus on: Business impact assessment, communication with stakeholders, time management, delegation, setting expectations
Q: Tell me about a time you made a mistake and how you handled it.
Focus on: Taking responsibility, immediate action to fix, communication, learning from the mistake, prevention measures
Q: Describe a situation where you had to learn a new technology quickly.
Focus on: Learning strategies, resources used, practice methods, asking for help, applying knowledge, results achieved
Q: How do you stay updated with technology trends?
Focus on: Continuous learning habits, resources (blogs, courses, certifications), hands-on practice, networking, applying new knowledge
Q: Tell me about a time you had to work under pressure.
Focus on: Stress management techniques, prioritization, clear communication, staying organized, maintaining quality under pressure
Q: Describe a time you went above and beyond for a user or team.
Focus on: Initiative, extra effort, user satisfaction, team benefits, personal motivation, positive outcomes
🎯 Key Qualities to Demonstrate
- Problem-solving: Analytical thinking and creative solutions
- Communication: Clear explanation of technical concepts
- Customer service: User-focused approach and empathy
- Adaptability: Flexibility in changing environments
- Teamwork: Collaboration and knowledge sharing
- Continuous learning: Staying current with technology
- Attention to detail: Thoroughness in troubleshooting
- Time management: Efficient prioritization and organization