portforwarding - Vagrant reverse port forwarding?

Question

I'm working on a web services architecture. I've got some software that I need to run on the native host machine, not in Vagrant. But I'd like to run some client services on the guest.

Vagrant's config.vm.forwarded_port parameter will open a port on the host and send the data to the guest. But how can I open a port on the guest and send the data to the host? (It's still port forwarding, but in the reverse direction.)

Answer 1

When you run vagrant ssh, it's actually using this underlying command:

ssh -p 2222 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o LogLevel=ERROR -o IdentitiesOnly=yes -i ~/.vagrant.d/insecure_private_key vagrant@127.0.0.1

SSH supports forwarding ports in the direction you want with the -R guestport:host:hostport option. So, if you wanted to connect to port 12345 on the guest and have it forwarded to localhost:80, you would use this command:

ssh -p 2222 -R 12345:localhost:80 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o LogLevel=ERROR -o IdentitiesOnly=yes -i ~/.vagrant.d/insecure_private_key vagrant@127.0.0.1

As Eero correctly comments, you can also use the command vagrant ssh -- -R 12345:localhost:80, which has the same effect in a much more concise command.