You must get a packet from computer 1 to computer 2 using the 7 layer OSI model.
Layer 7 – Application:
Talk to the green device on the left. He’ll tell you to look at the OSI poster on which you can read the different layers of the model. A key will be dropped on the floor. Use the KEY to pick it up. Use the key on the silver door on the right and you will learn that an email will be send.
Use the green button in the center to create a packet. Use the PACKET to pick it up and use the packet again on the stairs to go to the next layer.
Layer 6 – Presentation:
Look at the screen. Use the KEY from the screen to pick it up and return to the game. Use the key on the door on the right and enter the room with the machine. Use the packet on the machine to compress and encrypt the packet. Use the changed PACKET again to pick it up and use the packet on the stairs to go to the next layer.
Layer 5 – Session:
Talk to the device on the left. He’ll explain about the ‘operators’ and drop a key on the floor. Use the KEY to pick it up and use the key on the door on the right. Use the packet on the picture with the phone. Use the PACKET again to pick it up and use the packet on the stairs to go to layer 4.
Layer 4 – Transport:
Use the text to get the KEY. Read about the port numbers. Look at the different ports to learn their numbers. Use the key on the door on the right to go to the next room. Use the packet on the machine in the middle to create segments for the correct port (25 in this case). Use port 25 on the wall to take your PACKET again. Use the packet on the stairs to go to the next layer.
Layer 3 – Network:
Talk to the router to learn the right way to the other side. Use the bottom path and walk to the right. At the intersection turn left and follow the path to the right. At the next intersection do the same: turn left and follow the path to the right. Walk through the cloud and on the other side talk to the router again.
At the first intersection go down and keep following the path down. At the bottom of the screen it will turn to the right. At the first possible left (or north if you wish), turn left and follow that path until the other side.
Use your packet on the machine to prepare it for layer 2. Use the PACKET again to pick it up and use the packet on the stairs to go to the next layer.
Layer 2 – Session:
Click on the LLC and read the text. Take the ON-BUTTON from the text and return to the game. Use the on-button on the arrows in the middle to power up the switch. Walk to the right to open the pipe and use the packet on the opening of the pipe. Your packet is adjusted for the next level and you can use the PACKET to put in in the inventory. Use the packet on the stairs to go to the final layer.
Layer 1 – Physical:
Talk to the device to get the KEY. Use the packet on the blue bar to change it into bits. Use the PACKET to take it and use the key on the door on the right. Look at the hub on the wall to take the PELLET. Return to the game and use the pellet on the green monster. The use the packet on the mouth of the monster.
Move to the computer on the right.
Layer 1 – Physical:
Use the PACKET to pick it up and use the key on the door on the right. Use the packet on the blue bar to change it from bits into frames. Use the PACKET to pick it up and use the packet on the ladder for the next layer.
Layer 2 – Session:
Use the frame on the opening of the pipe to convert it. Pick up the PACKET again and use it on the ladder.
Layer 3 – Network:
Use the packet on the machine to take the IP address off. Pick up the PACKET and use the packet on the ladder for the next layer.
Layer 4 – Transport:
Use the packet on the machine. Use the packet again on port 25 to prepare it as an email. Take the PACKET from port 25 and use it on the ladder.
Layer 5 – Session:
Use the packet on the picture. It’s now ready for the presentation. Take the PACKET again and use it on the ladder.
Layer 6 – Presentation:
Put the pacet on the machine in the middle to prepare it for the application. Use the PACKET again and use it on the ladder to go to the final layer.
Layer 7 – Application:
Talk to the device on the left. Now you have to find the correct application. Since it’s an email, use the packet on the application at the top. You have mail!
Game source: A copy of the game was found here on the internet.