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How to debug "Vagrant cannot forward the specified ports on this VM" message

I'm trying to start a Vagrant instance and getting the following message:

Vagrant cannot forward the specified ports on this VM, since they
would collide with another VirtualBox virtual machine's forwarded
ports! The forwarded port to 4567 is already in use on the host
machine.

To fix this, modify your current projects Vagrantfile to use another
port. Example, where '1234' would be replaced by a unique host port:

  config.vm.forward_port 80, 1234

I opened VirtualBox, but I don't have any running boxes at the moment, so I'm stumped. How can I figure out which process is listening on 4567? Is there a way to list all Vagrant boxes running on my machine?

Thanks, Kevin

Solution

  • As message says, the port collides with the host box. I would simply change the port to some other value on the host machine. So if I am getting error for

    config.vm.forward_port 80, 1234

    then I would change it to 

    config.vm.forward_port 80, 5656

    As 1234 might be used on my host machine.

    For actually inspecting ports on any machine, I use the tcpview utility for that OS and get to know which port is used where.