How do I force FileZilla to use OpenVPN?

Question

I want to connect to a public SFTP server, but not via its public IP but over an OpenVPN connection because the server refuses SSH connections from the Internet. I'm using OpenVPN on a Windows 7 machine with the TAP driver.

How do I configure FileZilla to use the OpenVPN connection?

Answer 1

FileZilla don't need to specifically know over what connection you want to communicate. You can just use the SFTP server's VPN IP and not it's public IP as the host name in FileZilla. In this way FileZilla will connect through the VPN without doing anything different.

If you try using the SFTP server's domain name as host name for FileZilla, you might need to manually configure your windows to use the VPN's DNS. OpenVPN sometimes have problems with doing this automatically.

You can check the server's private IP from the network configuration settings on the server if you have access to it. Or, if you don't have server access, you can try and check it from one of the local LAN clients by looking at it's configuration or just pinging the server.

On some LAN configurations clients from the VPN connection can not access servers that are on the DMZ, in such configuration your request is not possible. In this case you would not be able to connect the with it's private IP when connected through VPN. This should be checked with a network administrator.

Answer 2

The public SFTP server must be running an OpenVPN instance that is configured to be part of that same virtual network. If this is not the case, OpenVPN cannot help you.

If this is the case, the SFTP server will be listening on its OpenVPN IP address. It's likely the first address in the subnet. When you start up your OpenVPN instance, you should be able to ping that address.

For example, on a server I have OpenVPN set up as a server. It is set to accept incoming connections on its public IP, port 22220, and to create a virtual network using the private IP address range 192.168.64.1 to 192.168.64.126.

On the client end, OpenVPN is set up to connect to my server's public IP address, port 22220. I start my OpenVPN client, it connects to the OpenVPN server on its IP, port 22220, and a tunnel is established.

At that point I can type ping 192.168.64.1 and reach the server that OpenVPN is running on, and since this is on the virtual network I defined, it is for sure going through the OpenVPN tunnel.

So if I had an FTP server running on that system, I'd tell it to listen on 192.168.64.1. You could then point your FTP client to 192.168.64.1 and connect, through the tunnel.