You must reconfigure the guest so it will get its own IP address:

• Shutdown the guest
• In the guest's VirtualBox settings, choose Network and switch the network adapter type to Bridged
• Restart the guest
• Read the guest's IP address from the output of ifconfig (Unix) or ipconfig (Windows)
• You can now connect to this IP address using HTTP, SSH, etc.

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Note that by doing this your VirtualBox guest is fully exposed on the local network, just like your host machine.