(Analysis and prevention of sniffer in Ethernet
0 Introduction
Sniffe: sniffer to is an effective tool used by experienced network administrators to solve some data transmission problems
For example, if the network performance is very low and we don't know what the problem is, we can use sniffer to
Make accurate problem judgments With the help of sniffer,...........
1snifer's working principle
Ethernet is a kind of shared media. It will forward packets received by one port to all ports after they are copied. This
This means that all hosts on the same network segment can access all data transmitted on the media When the network interface is in a normal state,
Although all the machines on the network can "hear" all the data through the network, they generally only respond to the following two data frames: the first is the destination
Data frame whose address is the local address; The second is broadcast frame This can be achieved by identifying the destination address of the received packet_
If the packet is not sent to itself, discard it (in other words, assume that workstation a and workstation C are in the same network segment,
Workstation a does not capture data belonging to workstation C, but simply ignores the data).............)
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