When we recently tried out the vagrant-aws plugin with Vagrant 1.1.5, we ran into an issue with SSH agent forwarding. It turned out that Vagrant was forcing IdentitiesOnly=yes without an option to change it to no. This forced Vagrant to only look at the private key we listed in the Vagrantfile for the AWS provider.
I wrote up our experiences in a blog post. It may turn into a pull request at some point.
In addition to adding "config.ssh.forward_agent = true" to the vagrant file make sure the host computer is set up for agent forwarding. Github provides a good guide for this. (Check out the troubleshooting section).
If you are on Windows, SSH Forwarding in Vagrant does not work properly by default (because of a bug in net-ssh). See this particular Vagrant bug report: https://github.com/mitchellh/vagrant/issues/1735
"0.0.0.0" is way take request from external connection.
then
ssh -p 2333 vagrant@192.168.2.101 (change to your own host ip address, dud)
will working just fine.
Do thank me, Just call me Leifeng!
On Windows, the problem is that Vagrant doesn't know how to communicate with git-bash's ssh-agent. It does, however, know how to use PuTTY's Pageant. So, as long as Pageant is running and has loaded your SSH key, and as long as you've set config.ssh.forward_agent, this should work.