Inboot2docker startAfter that, the following three environment variables need to be set:DOCKER_HOST,DOCKER_CERT_PATH,DOCKER_TLS_VERIFY.

If boot2docker starts successfully under windows, you will be prompted as follows:

To connect the Docker client to the Docker daemon, please set:
 If you are running inside Windows Command Prompt (cmd.exe), copy and paste the
 following commands to your terminal to set the environment variables:
 set DOCKER_HOST=tcp://192.168.59.103:2376
 set DOCKER_CERT_PATH=C:\Users\${user}\.boot2docker\certs\boot2docker-vm
 set DOCKER_TLS_VERIFY=1
 
 If you are running inside PowerShell, copy or paste the following commands
 to your shell or run "boot2docker shellinit | Invoke-Expression" to set the
 environment variables:
 $Env:DOCKER_HOST = "tcp://192.168.59.103:2376"
 $Env:DOCKER_CERT_PATH = "C:\Users\${user}\.boot2docker\certs\boot2docker-vm"
 $Env:DOCKER_TLS_VERIFY = "1"

Copy and execute the three environment variables mentioned above, for example, in cmd of windows:

set DOCKER_HOST=tcp://192.168.59.103:2376
 set DOCKER_CERT_PATH=C:\Users\${user}\.boot2docker\certs\boot2docker-vm
 set DOCKER_TLS_VERIFY=1