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.

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# 🐍 `socket` Cheat Sheet (Cybersecurity Edition)

## 🔌 Create a Socket

```python
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)

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

👉 Used in:

* Port scanners
* Banner grabbing

---

## 📤 Send Data

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

* Must be **bytes** (`b""`)

---

## 📥 Receive Data

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

* `1024` = buffer size

---

## ❌ Close Connection

```python
s.close()
```

---

# 🔍 Port Scanner Example (core pattern)

```python
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)

```python
s.settimeout(1)
```

Without this, your scanner becomes a fossil 🦴

---

# 🖥️ Simple Server (Listener)

```python
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()
```

👉 Used in:

* Backdoor simulations
* Reverse shells (ethical labs only)

---

# 📡 UDP Socket (connectionless)

```python
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

s.sendto(b"Hello", ("127.0.0.1", 53))
```

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# 🧠 Useful Methods Quick List

* `socket()` → create socket
* `connect()` → connect to server
* `connect_ex()` → safer connect
* `send()` / `sendall()` → send data
* `recv()` → receive data
* `bind()` → attach to IP/port
* `listen()` → wait for connections
* `accept()` → accept connection
* `close()` → close socket

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# ⚠️ Common Mistakes

* Forgetting `.close()` → zombie sockets
* Not using timeout → slow scans
* Sending string instead of bytes → 💥 error
* Scanning too fast → gets blocked