Question.3226 - 2.1 Explain the meaning of each field of the following packet filtering rule. (13 points) Firewall rulePacket directionSource addressDest addressPacket typeSource portDest port ACK actionC Incoming ext 132.28.6.4 TCP 23 * * deny2.2 If a packet is permitted by the following packet filtering rule, that is, the packet matches the rule: Firewall rulePacket directionSource addressDest addressPacket typeSource portDest port ACK actionD Outgoing int ext TCP * 23 * permit 4.2.2.1: Who is the sender program (of the packet) and where is the sender (inside the firewall or outside the firewall)? (7 points) 5. 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) 6. 2.2.3: What are the IP address and port number of the receiver program? (7 points) 7. 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) 9. 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. 10. 2.2.7.1: Why rule D does not authorize this packet to go through the firewall? (8 points) 11. 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) 12. 2.2.7.3: Give a rule which authorizes this new packet to go through the firewall. (8 points) 13. 2.2.7.4: Give a rule which can block this new packet from going through the firewall. (8 points)
Answer Below:
The xxxxxxx of xxxx field xx the xxxxxxxxx packet xxxxxxxxx rule x Firewall xxxx value xxxxx C xxxxx - xx specifies xxx firewall xxxx that xxx firewall xxxxxxx for xxxxxx filtering xxxxxxxx rule x is xx be xxxxxxxx here xx Packet xxxxxxxxx value xxxxx incoming xxxxx - xxxxxx whether xxx packet xx coming xxxxxx the xxxxxxx or xxxxx out xx the xxxxxxx iii xxxxxx address xxxxx rsquo xxx rsquo xxxxxx the xxxxxx address xx the xxxxxx Since xxx packet xx entering xxx firewall xxxx outside xxx network xxx value xx lsquo xxx rsquo xxxxx for xxxxxxxx iv xxxx address xxxxx rsquo xxxxx -states xxx destination xxxxxxx of xxx packet xxxxx it xx to xx sent xxx value xx the xxxxxxxx address xx the xxxxxxxxxxx v xxxxxx type xxxxx rsquo xxx rsquo xxxxxxx the xxxxxxxxxxxxx protocol xx the xxxxxx Here xx is xxx so xxx transmission xx packet xx connection xxxxxxxx with xxxx reliability xxxxxxxx and xxxxxxxxx of xxxx maintained xx Source xxxx value xxxxx rsquo xxxxxx the xxxx address xx the xxxxxx of xxx packet xxxx which xxx packet xxx sent xxx Dest xxxx value xxxxx rsquo x gives xxx port xxxxxxx of xxx destination xx the xxxxxx through xxxxx the xxxxxxxxxx was xxxxxxxxxxx Here xxx value xx not xxxxxxxxx therefore xxx client xxx use xxx port xxx communication xxxxxxx port xxxxxxx above xxxx ACK xxxxx rsquo xxxxx - xxxxx the xxxxxxxxxxxxxx value xx the xxxxxx whether xx was xxxxxxxx or xxx lsquo xxxxx signifies xxxx the xxx field xx not xxx ix xxxxxx value xxxxx deny xxxxx - xxxxxx whether xx allow xxxxxx transfer xx not xxxxxx of xxx program xx the xxxxxx server xxx is xxxxxx the xxxxxxxx Receiver xx the xxxxxxx is xx external xxxxxx via xxxxxxxx and xx is xxxxxxx the xxxxxxxx IP xxxxxxx of xxx receiver xx can xx any xxxxxx connected xxxx the xxxxxxxx example xxxxx rsquo xxx port xxxxxx is xxxxx rsquo xxx computer xxxxx be xxx machine xx which xxx receiver xxxxxxx is xxxxxxx because xxx firewall xxxxxx any xxxxxxxx TELNET xxxxxxxxxx in xxxx case xxxxx sends xxx program xxxx internet xxx computer xx connected xx the xxxxxxxx No xxxx packet xxxxxx be xxx second xxxxxxxx packet xx signal xx the xxxx handshake xxxxxxx of xxx TCP xxxxxxx or xxxxxxxxxx because xxx ACK xxxxx is xxx set xx this xxxxxx cannot xx the xxxxx sub-step xxxxxx or xxxxxx of xxx -way xxxxxxxxx process xx the xxx session xx connection xxxxxxx the xxx field xx not xxx Rule x is xxxx for xxxxxxxx packets xxx thus xxxxxxxx packets xxxxx rule x is xxx permitted xxx field xx not xxx and xxxxxx port xx not xxxxxxxxx This xxxxxx is x part xx step xx TCP xxxxxxxxxx Rule x authorizes xxxx new xxxxxx to xx through xxx firewall xxxx C xxx block xxxx new xxxxxx from xxxxx through xxx firewallMore Articles From Computer
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