How to enable network into Windows VM from other VM?

In Enabling networking between two qubes, you should run sudo iptables -I INPUT -s <IP address of A> -j ACCEPT in destination VM but there isn’t iptables in Windows.

I find I can RDP to Windows without sudo iptables -I INPUT -s <IP address of A> -j ACCEPT in Windows after sudo iptables -I FORWARD 2 -s <IP address of A> -d <IP address of B> -j ACCEPT. This is an unexpected behaviour.