I am trying to configure network interfaces on remote machines using python. The surrounding context is that I have a service that provisions VM instances and is required to create appropriate network interfaces on the VM host for the instance to use. I am restricted regarding remote code execution.
My first idea was to use SSH and work with the remote /etc/network/interfaces (the remote machines are exclusively debian based).
Additionally, I stumbled upon pynetlinux and others using a python socket and fcntl to retrieve and configure local interfaces (interfaces.py using socket and fcntl). Obviously, the socket is only locally available but that got me thinking: Is it possible to use a python file-like object over SSH directly accessing remote network interfaces in the way socket.socket does?
I hope there is a way to achieve this, parsing and writing /etc/network/interfaces would work but the other solution is imho awesome.
Greetings and thanks in advance
Related
Can you advise me on the analogs of the socket library on Python? The task is this, I need to write a very simple script with which I could execute remote commands in cmd windows. I know how this can be implemented using the socket library, but I would like to know if there are any other libraries for such a case.
Sockets is a low level mechanism by which two systems can communicate each other. Your OS provides this mechanism, there's no analogs.
Next examples come from the application layer and they work with sockets in their lower communication layers: a socket open by your http server, usually 80 or 443 or a websocket open by your browser to communicate with your server. Or the DNS query that your browser executes when tries to resolve a domain name, also works with sockets between your PC and the DNS server.
I have just written some python server and client using tcp protocol. I am using linux, and want to connect to a windows machine which isn't in my local network. How can i do that? I know it is something about NAT, but i can't find out how to do it properly. Could you please give me step by step guide? Thanks.
Just use sockets? You need to ensure that the network the windows laptop is on is configured to forward a specified port to the laptop. (means it can be accessed externally) You can then use sockets to connect to the laptop on the port you designate.
I need to write a python script which connects to the host over SSH and then somehow connects to a service sitting on localhost and performs a little interactive session.
What first came to mind is to use Paramiko to do a local port forwarding and then use Pythons's sockets library to communicate with the service.
But working with Paramiko was quite a challenge and I haven't figured out how to fix some issues.
So I switched to pxssh and used just simple scenario:
conn.sendline('telnet {} {}'.format('localhost', port)
conn.expect('PASSWORD:')
conn.sendline(password)
...
But that telnet thing really bothers me.
And I think it's possible to establish SSH connection in such a manner that from Python's code prospective I just do data = open('somefile').read() which actually opens a somefile on a remote host and all traffic is being encrypted because of SSH.
I'm writing a Python script which connects to remote hosts over a (super complicated) SOCKS/SSL tunnel. I am able to establish connections to IPs in a remote intranet on any port.
What I'm hoping to do is set up this python script to use IP addresses in the local loopback range (127.0.x.x) to become (maybe with the help of the hosts file) a 'replica' of the remote systems, and hence enable me to use applications which don't support proxies. The problem is that I don't always know what ports they're trying to connect to. It seems the only way to work this out is to bind sockets to all 65536 ports, which seems a little crazy. So two questions:
Is it crazy? Can I just set up a python list of sockets from 1-65536?
Or is there a better way I should be doing this? Can I monitor connections to an IP somehow and bind the ports just before they're needed?
I want to avoid using too much platform-dependent or non-python code if possible.
EDIT: To clarify, I'm only writing the client here - I have no control over the server. Believe me, if I had control over the server side of it I would not be doing it with SOCKS/SSL/CRAM :)
What about going lower level and interfacing a library designed for network analyzers like pycap?
This way you could detect all connection attempts and find the ports that you need to expose or may be you can just route the packets directly assuming the library in addition to packet detection can also do packet injection (pypcap page says this feature is experimental).
This would IMO make sense in python only for slow applications however...
Pycap seems to be developed for linux, but the core capturing is done by libpcap and for windows there is a similar library winpcap.
Matt,
If using windows your best shot is something like OpenVPN over the tunnel. OpenVPN requires only one TCP port/stream and gives you a pair of virtual interfaces with full connectivity.
[updated]
It may be possible using a TUN/TAP driver on the client side. See this unix version for ideas.
Overview:
I have a device sitting on a local network to a computer that is sitting on an outside network. I would like to create a software program that allows me to seamlessly connect to the device from a computer on a different network. For purposes of this question, I've created a picture to help describe the network flow. What I need help with is what python packages I would need to develop the solution for this problem.
Details:
I have a computer MYPC (IP address 192.168.0.168) that is attached to the internet running through a proxy server (ROUTER1). I have full control over MYPC's environment, which is running Linux.
I have a second computer SOMESERVER (IP address 192.168.1.168) that is attached to the internet running through a proxy server (ROUTER2). In addition, SOMESERVER (IP address 10.0.0.159) is also attached to a local network (LOCAL). SOMESERVER is running windows. I have very limited control with SOMESERVER: I am able to send an executable to SOMESERVER that can run once before it is removed. I do not know the internet/world IP address of the ROUTER2 initially.
I have a device (DEVICE1) attached to SOMESERVER through LOCAL (IP address: 10.0.0.157).
I have another device (DEVICE2) attached to SOMESERVER through LOCAL (IP address: 10.0.0.158). DEVICE(x) runs linux. I have python on DEVICE(x) and I could install a pure python package if I needed to. However, I do not have the ability to compile for DEVICE(x).
I can connect between SOMESERVER and MYPC through the internet using SSH over ROUTER1 and ROUTER2. I can connect between SOMESERVER and DEVICE1 through the local network (LOCAL) using Telnet. I can connect between SOMESERVER and DEVICE2 through the local network (LOCAL) using Telnet.
I want to send a program to SOMESERVER that allows me seamless access over SSH and Telnet to DEVICE1 and DEVICE2 from MYPC. In addition, I want that program to be running python.
Here's a picture that helps explain the above problem:
Solution:
What I think I want is as follows. I need help with the details and what packages I might need to make it happen.
Part 1: The Dial Home Client and Server
Create a "dial home" server program (DIAL_HOME_SERVER) for MYPC which listens for any one dialing home and then will "dial into" any SOMESERVER that "dials home" using SSH.
Create a "dial home" client program (DIAL_HOME_CLIENT) for SOMESERVER which is downloaded as part of a package
Part 2: The Proxy Server
Create a ssh to telnet proxy server program (PROXY_SERVER) for SOMESERVER which listens for connections from MYPC and funnels them into a telnet connection to DEVICE(x).
Thanks to Greg Hewgill, it sounds like I can use Paramiko to pull together the PROXY_SERVER code on SOMESERVER. It appears that Paramiko also requires PyCryto, and the Windows binary for it can be found here.
Future Robustness
At a future date, the telnet connection will be replaced with an SSH client (dropbox on DEVICE(x)).
In Closing
I think the above will allow MYPC to connect "seamlessly", but the details of how to put together these programs is unknown to me. I already know how to package up a python program using Innosetup and/or py2exe. What I'd love to see is links pointing to different pieces of the solution so I can pull it all together. And then I can post it.
Thanks in advance!
I have to admit that I didn't quite follow all of your description, especially the "dial home" client/server part. However, your diagram seems sufficient for understanding.
Set up port forwarding on "router2" that forwards the incoming SSH port to your Windows server.
Write a Python program (you will probably find paramiko helpful) that runs on your Windows server, listens for SSH connections, and opens a telnet connection to one of your devices on the back end.
That seems sufficient to me. If you've got weird restrictions on the Windows server about only being able to run an executable once before it is deleted, that seems like another problem to solve that doesn't really relate to this tunnelling problem.