Serveo is my side project. It's similar to ngrok, but only uses SSH as the client.

With this feature, you can set up a reverse tunnel to an SSH server:

ssh -R my-alias:22:localhost:22 serveo.net (on the machine where sshd is running)

Then conveniently connect to it over the internet:

ssh -J serveo.net user@my-alias

"Show HN" should be added.