Networks Lab PCCSL507 Semester 5 KTU CS 2024 Scheme - Dr Binu V P

  Experiment Study of tcpdump Command 🎯 Aim To capture and analyze network packets using the tcpdump command. 📘 Objective By the end of this experiment, students will be able to: Capture live network traffic Filter packets based on protocol, port, or host Analyze packet-level communication Understand basic packet structure 📖 Theory The tcpdump command is a packet analyzer (sniffer) used to: Capture network packets in real time Display detailed information about each packet 👉 It works at a low level and can capture: TCP, UDP, ICMP traffic Packets to/from specific hosts or ports 👉 Commonly used for: Network troubleshooting Security analysis Debugging network applications 🧾 Syntax sudo tcpdump [options] [filter] 🔧 Common Options -i <interface> → Specify interface (e.g., eth0 ) -n → Do not resolve hostnames -c <count> → Capture limited number of packets -w <file> → Save packets to file -r <file...

  Experiment Study of nslookup Command 🎯 Aim To query DNS servers and obtain domain name or IP address mapping using the nslookup command. 📘 Objective By the end of this experiment, students will be able to: Resolve domain names to IP addresses Perform reverse DNS lookups Query specific DNS servers Understand DNS record types 📖 Theory The nslookup ( name server lookup ) command is used to: Query the Domain Name System (DNS) Translate: Domain name → IP address IP address → Domain name 👉 It helps in: Troubleshooting DNS issues Verifying DNS configuration Checking domain resolution 👉 It works in: Non-interactive mode (single query) Interactive mode (multiple queries) 🧾 Syntax nslookup [options] <domain_or_ip> [dns_server] 🔧 Common Usage Non-Interactive Mode: nslookup google.com Reverse Lookup: nslookup 8.8.8.8 🧰 Prerequisites Linux system Internet connectivity DNS configured 🔬 Procedure & Comma...

  Experiment  Study of bmon Command 🎯 Aim To monitor network bandwidth usage in real-time using the bmon command. 📘 Objective By the end of this experiment, students will be able to: Monitor real-time bandwidth usage of network interfaces Analyze incoming and outgoing traffic Compare bandwidth across multiple interfaces Understand graphical/text-based traffic representation 📖 Theory The bmon ( Bandwidth Monitor ) command is a tool used to: Display real-time network bandwidth usage Provide both text and graphical interface in terminal 👉 It shows: Data transfer rates (incoming & outgoing) Interface-wise bandwidth usage Traffic statistics in a visual format 👉 Compared to tools like iftop , bmon focuses more on: Interface-level monitoring rather than per-connection 🧾 Syntax bmon [options] 🔧 Common Options -p <interface> → Monitor specific interface -o <output> → Output format (e.g., ascii) -r <rat...

  Experiment:  Study of speedtest-cli Command 🎯 Aim To measure internet bandwidth (download and upload speed) using the speedtest-cli command. 📘 Objective By the end of this experiment, students will be able to: Test internet speed from the command line Measure download and upload bandwidth Analyze network performance Compare speeds under different conditions 📖 Theory The speedtest-cli is a command-line tool used to: Test internet speed using Speedtest.net servers Measure: Ping (latency) Download speed Upload speed 👉 It connects to the nearest or selected server and performs data transfer tests. 👉 Useful for: Network troubleshooting ISP performance analysis Lab performance evaluation 🧾 Syntax speedtest-cli [options] 🔧 Common Options --simple → Simple output (minimal details) --list → List available test servers --server <id> → Select specific server --bytes → Show speeds in bytes instead of bits ...

  Experiment Study of nmcli Command 🎯 Aim To configure and manage network connections using the nmcli command in Linux. 📘 Objective By the end of this experiment, students will be able to: View network devices and connections Connect to wired and wireless networks Configure IP settings Manage network profiles using CLI 📖 Theory The nmcli ( Network Manager Command Line Interface ) is used to: Control the NetworkManager service from the terminal Manage network connections (wired, Wi-Fi, VPN) Configure IP addresses, DNS, and gateways 👉 It is a modern and powerful alternative to manual configuration using ifconfig or ip . 👉 It works with: Devices (hardware interfaces) Connections (saved network profiles) 🧾 Syntax nmcli [OPTIONS] OBJECT COMMAND Common OBJECTS: device → Network interfaces connection → Network profiles general → NetworkManager status 🧰 Prerequisites Linux system with NetworkManager Root/sudo privileges f...

  Experiment Study of nmap Command 🎯 Aim To explore and analyze network hosts and services using the nmap command. 📘 Objective By the end of this experiment, students will be able to: Discover active hosts in a network Scan open ports Identify running services Understand basic network security scanning 📖 Theory The nmap ( Network Mapper ) command is a powerful tool used for: Network discovery Security auditing Port scanning 👉 It works by sending packets to target systems and analyzing responses. 👉 It can detect: Open ports Closed ports Filtered ports (blocked by firewall) 🧾 Syntax nmap [options] <target> <target> → IP address, hostname, or network range 🔧 Common Options -sS → TCP SYN scan (stealth scan) -sT → TCP connect scan -sU → UDP scan -p → Specify port(s) -A → Aggressive scan (OS + version detection) -O → OS detection -v → Verbose output -F → Fast scan (common ports only) 🧰 Prereq...