Unformatted text preview: router. The default = discard policy is in force. What do they try to achieve? Action Our Host Port External Host Port Block * * XYZ * Allow ABC 120 * * Question 2 (a) For the trusted systems, multilevel security is required. In this case, a subject at a high level may not convey information to a subject at a lower level. The multilevel secure system must enforce the concepts of No-read-up and No-writedown. Explain the concepts of No-read-up and No-write-down (b) Explain how the No-write-down rule is useful in the defense against the Trojan horse attack. (Please read the textbook, pages 334-336)....
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- Spring '10
- Packet filtering, Packet Filtering Router, packet-filtering router