Update.

tun_server_example.md

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+# TUN Server Client Example 
+
+This is an example spat out by an LLM regarding creating a TUN server and a TUN client. I thought it was a very complete example including the linux forwarding terminal commands to be enterered. 
+
+I thought it was worth saving such great example as a gist. 
+
+retoor.
+
+## TUN Server (tun_server.py):
+```python
+import os
+import struct
+import socket
+import select
+import fcntl
+import array
+import threading
+
+TUNSETIFF = 0x400454ca
+IFF_TUN   = 0x0001
+IFF_NO_PI = 0x1000
+
+def create_tun_interface():
+    tun = open('/dev/net/tun', 'r+b', buffering=0)
+    ifr = struct.pack('16sH', b'tun0', IFF_TUN | IFF_NO_PI)
+    fcntl.ioctl(tun, TUNSETIFF, ifr)
+    return tun
+
+def setup_routing(tun_name):
+    os.system(f'ip addr add 10.0.0.1/24 dev {tun_name}')
+    os.system(f'ip link set {tun_name} up')
+    os.system('echo 1 > /proc/sys/net/ipv4/ip_forward')
+
+def handle_client_traffic(tun, sock):
+    while True:
+        readable, _, _ = select.select([tun, sock], [], [])
+        for fd in readable:
+            if fd is tun:
+                packet = os.read(tun.fileno(), 2048)
+                sock.send(packet)
+            elif fd is sock:
+                packet = sock.recv(2048)
+                os.write(tun.fileno(), packet)
+
+def main():
+    tun = create_tun_interface()
+    setup_routing('tun0')
+
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.bind(('0.0.0.0', 5000))
+    sock.listen(1)
+
+    print("[*] Waiting for client connection...")
+    client, addr = sock.accept()
+    print(f"[+] Connection from {addr}")
+
+    handle_client_traffic(tun, client)
+
+if __name__ == '__main__':
+    main()
+```
+
+
+## TUN Client (tun_client.py):
+```python
+import os
+import struct
+import socket
+import select
+import fcntl
+import threading
+
+TUNSETIFF = 0x400454ca
+IFF_TUN   = 0x0001
+IFF_NO_PI = 0x1000
+
+def create_tun_interface():
+    tun = open('/dev/net/tun', 'r+b', buffering=0)
+    ifr = struct.pack('16sH', b'tun0', IFF_TUN | IFF_NO_PI)
+    fcntl.ioctl(tun, TUNSETIFF, ifr)
+    return tun
+
+def setup_routing(tun_name, server_ip):
+    os.system(f'ip addr add 10.0.0.2/24 dev {tun_name}')
+    os.system(f'ip link set {tun_name} up')
+    os.system(f'ip route add default via 10.0.0.1 dev {tun_name}')
+
+def handle_server_traffic(tun, sock):
+    while True:
+        readable, _, _ = select.select([tun, sock], [], [])
+        for fd in readable:
+            if fd is tun:
+                packet = os.read(tun.fileno(), 2048)
+                sock.send(packet)
+            elif fd is sock:
+                packet = sock.recv(2048)
+                os.write(tun.fileno(), packet)
+
+def main():
+    SERVER_IP = '1.2.3.4'  # Replace with your server's IP
+    
+    tun = create_tun_interface()
+    
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.connect((SERVER_IP, 5000))
+    
+    setup_routing('tun0', SERVER_IP)
+    
+    handle_server_traffic(tun, sock)
+
+if __name__ == '__main__':
+    main()
+```