python bind socket.error: [Errno 13] Permission denied

Question

I have a python script which gets packets from a remote machine and writes them (os.write(self.tun_fd.fileno(), \'\'.join(packet))) to a tun interface gr3:

Answer 1

You can't bind to port numbers lower than 1024 as a unprivileged user.

So you should either:

• Use a port number larger than 1024 (recommended)
• Or run the script as a privileged user

Harder, but more secure solution if it's really necessary to accept from 111:

• Run the as unprivileged on a higher port, and forward port 111 to it externally.