If you have many different remote devices behind NATs or firewalls, a cool trick to access them all via EC2 server (or such) is to setup Remote Forwarding via UNIX socket on the server side, to devices' port 22. Preferably, UNIX socket filenames should start with a common prefix, so an SSH config can be written that will use ssh+socat in a ProxyCommand to establish the connection.
It's amazing how lightweight this method actually is. I have managed to connect hundreds of devices using a single EC2 nano instance.
I think the more modern ProxyJump rule is superior for this. Just let it manage the actual TCP forwarding for you automatically. It's just the normal "bastion host" concept.
Particularly, you can use name patterns to apply the same rule broadly, assuming you have some systematic naming scheme for your eventual target devices.
Do you have more info on this method? How is the remote forwarding actually done?
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