# Step080

Step080 Scapy lab, using Python3 and Scapy2.7.0. Read the files and run in your own Linux lab. The target is127.0.0.1; the changed source is127.0.0.2. Live verification used a Linux container without an external network. Windows was tested only for assembly and constructed-response classification.

```sh
python3 -m venv .venv
.venv/bin/python -m pip install -r requirements.txt
.venv/bin/python packet_lab.py build
.venv/bin/python reproduce.py --offline
# Terminal A
python3 -m http.server 9999 --bind 127.0.0.1
# Terminal B
sudo .venv/bin/python syn_scan.py --ports 9999
sudo .venv/bin/python packet_lab.py echo
sudo .venv/bin/python packet_lab.py sniff
sudo .venv/bin/python packet_lab.py source
# After stopping the manual server
sudo .venv/bin/python reproduce.py
```

Stop your own manual server with Ctrl+C to free9999 before running the reproducer; do not stop other services. No response does not prove filtering. A real firewall dropping SYN was not reproduced. Capture duplicates vary by environment. The reproducer closes its own servers and sockets; no host firewall changes are made. On Windows, create the venv with py -m venv .venv, then use .venv\Scripts\python.exe for installation, build and --offline. Live commands target Linux.

https://infosec.3001.co.kr/en/step-080-introduction-to-scapy/