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2026-04-23 18:00:21 +02:00

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The socket module is where Python stops being polite and starts speaking raw network 🧩📡 Here’s a clean, practical cheat sheet you’ll actually use when building cyber tools.

🐍 `socket` Cheat Sheet (Cybersecurity Edition)

🔌 Create a Socket

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

AF_INET → IPv4
SOCK_STREAM → TCP
(use SOCK_DGRAM for UDP)

🌐 Connect to a Target (Client)

s.connect(("127.0.0.1", 80))

👉 Used in:

Port scanners
Banner grabbing

📤 Send Data

s.send(b"GET / HTTP/1.1\r\nHost: example.com\r\n\r\n")

Must be bytes (b"")

📥 Receive Data

response = s.recv(1024)
print(response.decode())

1024 = buffer size

❌ Close Connection

s.close()

🔍 Port Scanner Example (core pattern)

import socket

target = "127.0.0.1"

for port in range(1, 1025):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(2)

    result = s.connect_ex((target, port))

    if result == 0:
        print(f"Port {port} is open")

    s.close()

🔥 Key trick:

connect_ex() returns 0 if open (no crash, cleaner)

⏱️ Timeout (avoid freezing forever)

s.settimeout(1)

Without this, your scanner becomes a fossil 🦴

🖥️ Simple Server (Listener)

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(("0.0.0.0", 4444))
s.listen(1)

conn, addr = s.accept()
print(f"Connection from {addr}")

data = conn.recv(1024)
print(data.decode())

conn.close()