Computer Networking - Firewalls

2.1 Explain the meaning of each field of the following packet filtering rule. (13 points)

2.2 If a packet is permitted by the following packet filtering rule, that is, the packet matches the rule:

2.2.1: Who is the sender program (of the packet) and where is the sender (inside the firewall or outside the firewall)? (7 points)

2.2.2: Who is the receiver program (of the packet) and where is the receiver (inside the firewall or outside the firewall)? (7 points)

2.2.3: What are the IP address and port number of the receiver program? (7 points)

2.2.4: Could computer 168.3.144.1 be the machine on which the receiver program is running? Why? (8 points

2.2.5: Could this packet be the second sub-step packet (or signal) of the 3-way handshake process of the TCP session (or connection)? Why? (8 points)

2.2.6: Could this packet be the third sub-step packet (or signal) of the 3-way handshake process of the TCP session (or connection)? Why? (8 points)

2.2.7: After the receiver program receives this packet, if the receiver wants to send a packet back to the sender, the above rule (rule D) does not authorize this packet to go through the firewall.

2.2.7.1: Why rule D does not authorize this packet to go through the firewall? (8 points)

2.2.7.2: A TCP connection has 3 steps (or phases): establish the connection, messages back and forth, terminate the connection. Is this packet part of Step 1, Step 2, or Step 3? (8 points)

2.2.7.3: Give a rule which authorizes this new packet to go through the firewall. (8 points)

2.2.7.4: Give a rule which can block this new packet from going through the firewall. (8 points)