![]() My initial problem is solved, but I want to understand why. On the external host, the SSH port forwarding is configured to port 80, instead of 8282. Nginx is installed on the same server as the Python web service is and simply listens on port 80 and proxies to localhost:8282. I was able to gain access to the Python web service from the external host, by placing an Nginx proxy between the Python web server and the external host. For comparison here's the Python rver log, first accessing it locally from the server, then from the external host, using SSH port forwarding. The SSH port forwarding from the host, where I want to gain access: ssh -L 8181::8282 the subsequent requests on the host with curl, I've defined the environment variable http_proxy: export http_proxy=127.0.0.1:8181Īpparently the requests are not correct, as they're prepended by the IP address. The Python server, for simplicity's sake (serving an index.html, containing the string hello): python -m rver 8282 Usually this is restricted to port 443 (hint: if you make your sshd listen on 443 this will work with most of the public proxies even thought I do not recommend to do this for interop and security reasons). My issue is, that if I use port forwarding to directly forward my requests to the port, where the Python server is running (e.g. The proxy and the sshd are running on the same host in my example but all you need is any proxy that allows you to CONNECT to your ssh port. Full length question for completion here. I've spent more time that I'd like to admit, troubleshooting why access to my Python web server 404s. ssh_process = sp.Popen(,īufsize=0, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.I'm using SSH port forwarding - as marvelously illustrated and elaborated here - to access my server. The script above uses the subprocess library to execute ssh, and build the tunnel. Here’s a diagram showing SSH and SSH with a tunnel. proxy IP:PORT IP and port of SSH proxy to destination -c. You can also tunnel anything, so unencrypted services available only on the server can be used remotely. sshaddress Pure python ssh tunnel utils Version 0.4.0 positional arguments: sshaddress SSH. It’s only available when you’re logged on. What’s nice about this is, you don’t have a socket permanently open. SSH manages this connection, and when you log out of the remote machine, the tunnel is also taken down. The following forwards port 3308 on the local machine to port 3306 on the remote machine 3306 is what MySQL runs on: ssh -元308:localhost:3306 SSH has a feature where it can forward a local port to a specific port on the remote machine, creating an encrypted tunnel for your traffic. I’m not certain if one is better than the other.) SSH tunnels (It’s also possible to do the encryption on the MySQL server’s socket – and require that specific certificates are provided. ![]() Next step is to turn this into a decorator, so we can create the function to perform the database operations, and wrap it with code that will transform it to execute the operations remotely. The passwords and other information should be in configuration files, not in the code. If (output.find('Welcome to Ubuntu') != -1): ![]() Please run this script = sp.communicate() Print "Critical error, cannot bind to the address." If (output.find('bind: Address already in use') != -1): ![]() # should probably run this before we try to start another one Ssh_process = sp.Popen(,īufsize=0, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.STDOUT ) It turns out to be a little difficult… but after some effort, the following script did what I needed:įrom nbstreamreader import NonBlockingStreamReader as NBSR So, I need to create scripts that will automatically log in to the server, open a tunnel, connect to the database server through this tunnel, and then execute SQL statements. If you don’t know what SSH tunnels are, there’s an explanation below. (The SSH connection will eventually require key pairs, and disallow regular passwords.) We’re accessing our database through an SSH tunnel, rather than via a regular encrypted socket. Lately, though, I have needed to write scripts that automate routine operations on a remote system, and we need the security barriers to be a little higher than in the “old days”. Like all sysadmins, I write scripts to automate routine operations. A demo of how to incorporate SSH tunnels into a Python system administration script.
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