9. Networking Rehash Bob is an insecure programmer and is using AnotherSketchyCorp's WiFi Network. (a) Bob is using FTP to download some potentially useful files from a server on the net work. However, the command keeps failing with the message 'connection refused" Explain which type of FTP is being used, how you can tell, and the source of the error. (b) Bob believes there may be a malicious entity on the network, searching for open ports on devices. Explain how Bob can locate the malicious entity's IP address. (c) Bob believes that the culprit was using Nmap. Explain how this tool works. (d) Bob is sure that he's located the IP address that belongs to the malicious entity. He contacts the admin of the network to change the password, but is afraid that the mai- cious entity may not need to re-authenticate. What can Bob do on his own (with no involvment of the network admin) to force the malicious entity to re-authenticate