How to setup Vagrant ssh agent forwarding?

Question

My goal is to connect from a VirtualBox VM to another machine using the ssh key authentication. I have created the VM with Vagrant (1.0.5). I have also enabled config.ssh.forward_agent = true (as suggested in this post). Sadly, the ssh forwarding does not seem to be working.

These are the steps (on fresh ubuntu with vagrant and virtualbox):

1. Log from the host machine to VM (when I use --debug, I see that the forwarding is enabled)

   vagrant ssh

2. Log from VM (ubuntu 12.04 with injected vagrant ssh key) to external machine

   ssh -A sk@192.168.0.1
   

   to get: Permission denied.

Do I need to perform any additional step to make it work? People advice to use ssh-add -K. It is not clear for me on which machine.

Answer 1

I could not make the ssh forwarding working. My solution is to simply generate new ssh key on the VM:

1. Log to the VM: vagrant ssh
2. Generate a new ssh key on the VM: ssh-keygen
3. Upload the new public ssh to 192.168.0.1: I do it manually. It could be automatize.
4. ssh -A sk@192.168.168.0.1 works