Consider a distributed denial of service (DDOS) attack, Assume the attacker has compromised a number of broadband connected computers to use as zombie systems. If the ISP provides a maximum uplink data rate of 7.5 Mbps in cable service, what is the maximum number of 256-byte ICMP echo request (ping) packets a single zombie computer can send per second? How many such zombie systems would the attacker need to flood a target server in an organization that has: A. Fast Ethernet. B. Gigabit Ethernet.

Networked computers When many senders seek to share the same medium, a data collision occurs. Where, and with what procedures, can this be prevented, if at all? Can we be confident that no passengers will be hurt if we take these precautions? Is there anything further we can do to fix this problem?

Consider a distributed denial of service (DDOS) attack, Assume the attacker has compromised a number of broadband connected computers to use as zombie systems. If the ISP provides a maximum uplink data rate of 768 kbps in cable service, what is the maximum number of 128-byte ICMP echo request (ping) packets a single zombie computer can send per second? How many such zombie systems would the attacker need to flood a target server in an organization that has: A. Fast Ethernet. B. Gigabit Ethernet.

Please explain what subnet mask 255.255.255.252 (/30) is and how it can be used to enhance network security with an example.

How can an attacker with host access (either an untrustworthy host, or an attacker who has compromised the host.  This is also known as a host attack) attack a system that uses passwords to authenticate users, and which stores the passwords in plain text?

Give an example of how a full denial of service attack on a user (in which the user gets no response from the computer) results in a significant issue for that user. Another example is offered in which a 10% denial of service (that is, the user's computation advances but at a 10% slower pace than normal) is a significant issue for that user. Illegal access to a computer system may result in a 10% denial of service attack against legitimate users of that computing system. If so, how would you proceed?

Question 20 Based on the previous question (UNIX passwords are derived by encrypting a public salt 1000 times with the password). Assume that passwords are limited to the use of the 52 English letters (both lower and upper cases) and that all passwords are 6 characters in length. Assume a password cracker capable of doing 6 million encryptions per second. How long will it take to crack a password with brute-force on a UNIX system, on average? (answer is an integer, the unit must be in seconds) Your Answer: Answer