Module 2 - Computer Networking

Lab 1: Test Connectivity

• Can you ping your gateway and observe the TTL value?

• Can you ping a public server such as 8.8.8.8?

• Can you ping a domain name (e.g., google.com) and does DNS resolution work?

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Lab 2: Essential Networking Commands

• How do you display all network interfaces?

• What is the route to google.com when using traceroute?

• What entries appear in your ARP table?

• What does your routing table show?

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Lab 3: DNS and Name Resolution

• What results do you get when using nslookup or dig to resolve www.guvi.com?

• What is the IP address of your DNS server?

• What happens after you flush and recheck the DNS cache?

• What is the difference between recursive and iterative DNS queries?

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Lab 4: Using Traceroute

• What does a traceroute to google.com look like?

• How many hops does the traceroute show?

• Which hop in the path belongs to your ISP?

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Lab 5: Check Host Reachability with telnet/nc

• Is port 80 on the target server reachable?

• Is SSH port 22 reachable?

• What happens when you test a closed port?

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Lab 6: Default Gateway & Routing Table

• What does your routing table display?

• How do you add a temporary static route to another network?

• How do you delete that static route?

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Lab 7: Network Security and Attack Simulation

• What happens when you simulate a simple ping flood locally?

• Do you see any unusual open connections using netstat?

• What are effective mitigation techniques for DDoS and MITM attacks?

• Which open ports and services does an nmap scan reveal?

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Lab 8: Hosts File Resolution Priority

• What happens when you add a fake entry for facebook.com in /etc/hosts?

• Does curl resolve to the fake IP?

• What happens after removing the entry and testing again?