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hack proofing your network second edition phần 7

Khả năng để truyền tải kết thúc lên được mức độ cơ bản nhất của bảo mật được thực hiện. Ngay cả những yếu nhất nhất từ xa mở rộng dịch vụ truy nhập không có thể bị tấn công bởi một người dùng không tin cậy nếu người dùng mà không có phương tiện để có được một tin nhắn đến hệ thống dễ bị tổn thương. | Spoofing Attacks on Trusted Identity Chapter 12 459 Ability to transmit ends up being the most basic level of security that gets implemented. Even the weakest most wide-open remote access service cannot be attacked by an untrusted user if that user has no means to get a message to the vulnerable system. Unfortunately depending upon a firewall to strip the ability to transmit messages from anyone who might threaten your network just isn t enough to really secure it. For one unless you use a military-style firewall read air firewall or a complete lack of connection between the local network and the global Internet excess paths are always likely to exist.The Department of Defense continues The principle underlying response planning should be that of graceful degradation that is the system or network should lose functionality gradually as a function of the severity of the attack compared to its ability to defend against it. Ability to Respond Can It Respond to Me One level up from the ability to send a message is the ability to respond to one. Quite a few protocols involve some form of negotiation between sender and receiver though some merely specify intermittent or on-demand proclamations from a host announcing something to whomever will listen.When negotiation is required systems must have the capability to create response transmissions that relate to content transmitted by other hosts on the network. This is a capability above and beyond mere transmission and is thus separated into the ability to respond. Using the ability to respond as a method of the establishing the integrity of the source s network address is a common technique. As much as many might like source addresses to be kept sacrosanct by networks and for spoofing attacks the world over to be suppressed there will always be a network that can claim to be passing an arbitrary packet while in fact it generated it instead. To handle this many protocols attempt to cancel source spoofing by transmitting a .