Prisoner_of_Ice
Member | Редактировать | Профиль | Сообщение | Цитировать | Сообщить модератору Alukardd ну вообще, это ссылка на INTERNET PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION. там нет указаний об использовании вроде бы, там описание что это есть такое The following internet options are defined: Loose Source Routing. Used to route the internet datagram based on information supplied by the source. © и далее по тексту Добавлено: в общем вот причины: Цитата: In theory, there is an alternative way to find this type of information with some implementations of traceroute. Some versions of traceroute support loose source routing, the ability to specify one or more intermediate hops that the packets must go through. This allows a packet to be diverted through a specific router on its way to its destination. (Strict source routing may also be available. This allows the user to specify an exact path through a network. While loose source routing can take any path that includes the specified hops, strict source routing must exactly follow the given path.) To construct a detailed list of all devices on a path, the approach is to use traceroute to find a path from the source host to itself, specifying a route through a remote device. Packets leave the host with the remote device as their initial destination. When the packets arrive at the remote device, that device replaces the destination address with the source's address, and the packets are redirected back to the source. Thus, you get a picture of the path both coming and going. (Of course, source routing is not limited to just this combination of addresses.) At least, that is how it should work in theory. In practice, many devices no longer support source routing. Unfortunately, source routing has been used in IP spoofing attacks. Packets sent with a spoofed source address can be diverted so they pass through the spoofed device's network. This approach will sometimes slip packets past firewalls since the packet seems to be coming from the right place. This is shown in Figure 4-3. Without source routing, the packet would come into the firewall on the wrong interface and be discarded. With source routing, the packet arrives on the correct interface and passes through the firewall. Because of problems like this, source routing is frequently disabled. Figure 4-3. IP source spoofing см. по ссылке ниже One final word of warning regarding traceroute--buggy or nonstandard implementations exist. Nonstandard isn't necessarily bad; it just means you need to watch for differences. For example, see the discussion of tracert later in this chapter. Buggy implementations, however, can really mislead you. | читать тут: Network Troubleshooting Tools а так же тут: Security Assessment of the Internet Protocol version 4 | Всего записей: 334 | Зарегистр. 24-11-2005 | Отправлено: 23:43 22-04-2012 | Исправлено: Prisoner_of_Ice, 23:55 22-04-2012 |
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