Here are the commands on how to accomplish this task.

Note: If your Hyper-V is internet facing, disabling the firewall is not recommended.

To disable the firewall in the currently running profile, you can issue the command:

netsh advfirewall set currentprofile state off

And re-enable with:

netsh advfirewall set currentprofile state on

OR
From the command line

netsh advfirewall set allprofiles state off

Using Powershell

Set-NetFirewallProfile -Profile Domain,Public,Private -Enabled False