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OpenVPN is an open source VPN daemon
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Unfair treatment for "Stub" Compression push? #551

Open ghost opened 1 month ago

ghost commented 1 month ago

I understand OVPN-DCO does not support any kind of compression, but it refuses to connect when compression stub is pushed by VPN provider that does not support compression. NordVPN stopped using compression as soon as VORACLE attack was discovered several years ago, but NordVPN does perform compression stub push. Pushing compression stub only enabled packet framing compression and that means there may only be a possibility compression push at a later time. NordVPN never pushes compression at any later time. Can it be that OVPN-DCO does not treat compression stub pushes fairly and just assumes that compression is eventually pushed? Why can't it just disconnect upon detecting actual compression instead of making such an assumption?

I'd also like to try some VPN providers that are known to fully support OVPN-DCO, but I don't know which ones do...

cron2 commented 1 month ago

Please send a logfile showing the connection, PUSH_REPLY, and OpenVPN's reaction to it.

(Also, this is not really a "DCO" issue, which is about the actual kernel code, and you see a userland effect - so I'll move this to "openvpn")

schwabe commented 1 month ago

We also implemented compress migrate to allow setups that used compression to move completely away from it instead of using stub. Also dco is only enabled if the config does not contain stub compression. And when it is enabled the client does not announce stub comprssion. So please share a log since that sounds weird.

ghost commented 1 month ago

Here are 2 configuration files (one with "compress migrate" and one without) and +2 logs to them (with sensitive identifiers and IP's replaced by "X".s): Migrate.log Migrate-OVPN-Config.txt NoMigrate-OVPN-Config.txt NoMigratre.log

I didn't want to spam these forums with questions and decided to just post the most important ones here as secondary side-issues, but I can move them to official OpenVPN Community forums if that's a better choice:

schwabe commented 1 month ago

compress migrate is a server option. It is something the server has to put in. In this case your VPN provider. stub compression should just not be used anymore and we provide proper tools to move away from that but if your VPN sticks to old outdated setttings there is nothing we can do.

And on the second config without migrate. Either you modify the config to remove compression settings or NordVPN is pushing comp-stub to clients that do not support it. Either way it is all working like it should and there is no bugs or unexpected behaviour.

Please sort that out with NordVPN support and have them update their configs/servers to modern standards.

There are no plans to integrate wireguard into OpenVPN.