GNU/Linux Bondging/Teaming for weak connections - best to do at VPN or OS level?

[djbclark 0]

I see some competitors, e.g. https://speedify.com/linux-vpn/ advertise "Use Multiple Internet Connections at Once on Linux."

Is this possible to do using AirVPN, or is this really something that is best done at the Operating System level, and then point Eddie at the right network interface?

Situation: Laptop with two USB Wifi interfaces, both with iffy connections, but to the same network.

Although it would be nice to have it also be able to use multiple networks, which I'm guessing would have to be done on the VPN level. In my case, this would be adding an XFINITY wifi hotspot randomly nearby, which I have a login to via my dad, to my non-Xfinity internet service. I could probably even triple up via the public library across the street with another USB adapter, giving seamless roaming to and from the library which would be nifty 🙂

[OpenSourcerer 1447]

4 hours ago, djbclark said:

Is this possible to do using AirVPN, or is this really something that is best done at the Operating System level, and then point Eddie at the right network interface?

Neither. AirVPN does not bond multiple connections to the same server. In fact, every connection is highly independent.

I can also imagine it being somewhat impossible with OpenVPN. Take the key exchange for an example: The ingenuity of it is that both ends choose a secret value for themselves and end up with a symmetric key without knowing each other's secret value. Two clients and the server will create three different values resulting in two different keys, a clear violation of the end-to-end principle because it'd be, in fact, end-to-two-ends.
Taking into account the clients don't know each other (yet), how will you make sure both clients use the same value for that without letting the server preselect it and possibly create something that can be exploited in an attack? And if you don't let the server in on the knowledge, how will any client determine if there is a "twin", how are they going to exchange the same keys in a secure way (as Diffie-Hellman will create different keys)?

I don't know how Speedify solved these things, if at all.  That's probably why they don't use it, something of their own that's a trade secret will do juuust fine.