Often, your personal computer is connected to the Internet through a modem. This modem takes the outgoing packets from all the machines connected to it and set the source address to a single value (such as "Home"). Incoming packets are then mapped back to the original machines. Pause the simulation and look at the packet information before and after it passes through the modem.
To pass this level, send a ping request from Alice's computer to Google.
Remember: ping packets have a transport layer header called proto with the value ICMP