If you need to change the guest-assigned IP range for some reason, please refer to Section 9.11, “Fine-tuning the VirtualBox NAT engine”. As more than one card of a virtual machine can be set up to use NAT, the first card is connected to the private network 10.0.2.0, the second card to the network 10.0.3.0 and so on. The IP address thus assigned to the virtual machine is usually on a completely different network than the host. These commands used to configure the kernel-resident network interfaces and display IP address such as 10.8.0.1 or 192.168.2.254. The virtual machine receives its network address and configuration on the private network from a DHCP server integrated into VirtualBox. To find out the IP address of Linux/UNIX/BSD/macOS and Unixish system, you need to use the command called ifconfig on Unix and the ip command or hostname command on Linux. To your original Q, it is only VirtualBox that knows about the guest's simulated address: VirtualBox listens for replies to the packages sent, and repacks and resends them to the guest machine on its private network. To an application on the host, or to another computer on the same network as the host, it looks like the data was sent by the VirtualBox application on the host, using an IP address belonging to the host. The network frames sent out by the guest operating system are received by VirtualBox's NAT engine, which extracts the TCP/IP data and resends it using the host operating system.

the IP chain' it's VirtualBox, not the host as such, that does this: FOR NAT MODE (per comments) from the manual subsection on NAT mode virtual networking

Linux get ip from mac