How to debug slow VPN?

[dsp76]

I know OpenVPN is much slower than wireguard, which we used before cloudron. But now its pretty slow. How can I best analyze the situation, before I may blame my hoster?

We already made sure, its not the connection to the server itself.

[girish]

I haven't needed to do this myself but for a start, I would measure the transfer speed between the server and your PC/Mac with and without OpenVPN .

[dsp76]

Turns out, that it may now be related to VPN. The download speed of the particular server is pretty low. Thus I recognize it when I use the VPN.

[dsp76]

Update: Did tests with two different products of Contabo (VDS, VPS). Both have the same issue. Did a couple of tests, found out its often at specific times of the day (peak) and sporadic behaviour (at non peak times) when 2 downloads are fast and the third is slow.

Also tested now Deutsche Telekom (3 different locations in Germany) and Vodafone as providers.
Turns out, that at the same time I had at least 50-90 times faster speed with Vodafone.

The average download with 30-40 KBps at peak times via Deutsche Telekom for a server with 500Mbps (62,5 MBps) Interface is not acceptable.

Customer support tested on our server vs. speedtest.net. In this case the software connects to the best available server. The server then connected with almost maximum possible speed (https://twzn.de/zazuz).

From my perspective, there is a peering issue between the backbone Contabo uses and Deutsche Telekom. There are a couple of discussions in forums, that seem to confirm those issues since quite a while already.

Looks like I need to move to another hoster. Should be easy peasy with Cloudron, I hope...

(response from support is still open, will update here)

[dsp76]

Alright, after Contabo support confirmed, that they don't directly peer with Deutsche Telekom ... things didn't get better.

We now finally moved to Hetzner, which confirmed they do all the peering. I moved today with help of Cloudron. Was such a pleasure:

1. started backup on old server...
2. created virtual dedicated server (CCX33), which took <1 min in our existing client account
3. installed Cloudron on a fresh Ubuntu 24.04 LTS
4. waited for the backup to finish
5. copied the backup config file for restore into the new Cloudron instance, added password and passphrase
6. done in total effort of about 2h with 48 migrated apps...

Only some domains still pointed to the old server (with no running apps on them), which was fixed quickly and one custom app still needs some love.

Happy so far.
Network performance is a huge difference!

[humptydumpty]

I too moved recently from Contabo to Hetzner and noticed a huge improvement in disk and network speeds. At least you got a straight answer from Contabo support. I was never that fortunate. Glad your move went smoothly!

[Dont-Worry]

Hello,
I have the same issue since the beginning of my use of Cloudron. So I contacted OVH's support, we've done tests on my servers and VPS and we confirmed that the problem is not server side. I have 2gb download, and upload. But the OpenVPN is still very very slow. I tried to change the settings in the config file of OpenVPN. But it is still very far from 2gb.. Do we have any solution so far?

[dsp76]

Check the network speed with an SFTP connection directly to your server. Upload / download a file from your location to your server.

The speed check on our server performed by our hoster was also fine. No surprise - as the speed test software connects to the best available server, which might be connected on a different network than yours.

The direct test without VPN showed the same issue - so it was not related to VPN, but to the general connection between my office, homeoffice + other places and our server.