SFTP connection via proxy


i can´t find a setting in duplicaty to connect to a sftp server via proxy.
I tried it with winscp an it can connect trough proxy without any problems.
I think that duplicati uses sshnet as sftp client. The feature list of sshnet includes proxy support.
Am I missing these settings or is this somewhere hidden?


Welcome to the forum @abis

This is probably not going to end nicely, but let’s try a bit.

What proxy type works, and do you need authentication?
Implementations of proxies describes a few server types.
SOCKS in some flavor might be suitable for this purpose.

Do you control proxy or its host? Do you know what OS?

The proxy configuration is different per customer but they are all http proxys. But some have auth.
With my winscp test i could conntect via http and no auth to the sftp server.
The servers i control or try to use with duplicati are running windows server 2016/2019.

Edit: I could also use a webdav connection instead of the sftp. This also works with winscp.

It’s still not sounding hopeful, but some web proxies need configuration in some browsers, while there are also transparent web proxies that force web traffic through them, so don’t need any browser configuration.

Do you happen to know which you have? This sounds like multiple customer sites, making it more difficult.
Possibly a backup program more aimed at businesses would support bypassing corporate firewalls better.

There are some third-party programs such as Proxifier (payware) that might be able to help get by firewall.

I just noticed your edit about WebDAV. That might make things a little bit more possible thanks to the .NET Framework HttpClient.DefaultProxy Property which takes environment variables such as HTTPS_PROXY.

Couldn’t connect to minio server when proxy configured in linux was the previous attempt at getting this up.
You could first try setting an environment variable to a no-auth-required web proxy before starting Duplicati.

Or if you can’t get it to work, you could take a system (if one exists) without a firewall in the way, and see if configuring it to a non-existent web proxy can break it. You then at least know it got noticed. If that fails then

If you can manage to get standalone rclone going using the similar scheme that it gets from Go, then use Rclone destination storage type for Duplicati. If need be (to keep Duplicati from also seeing proxy variable), rclone can be invoked through a wrapper script that passes along all parameters – plus the proxy variable.

Can I use rclone with an HTTP proxy?

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Thanks for your help.
I will try your suggestions.

Proxy without auth seems to get its settings from the system and does work without doing anything special.
Proxy with auth dosen´t work because I can´t add the required creds anywhere.
But with Proxifier i got it to work.

I could only test webdav because the tested proxys block anything other than port 80,443.

Thanks for the help.

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