A sniffer is any tool, be it software or hardware, which collects information traveling along a network. This network can use any communication protocol: Ethernet, TCP / IP (the Internet is mainly based on this protocol), IPX or others. Sniffer software is generally used and the term in question refers to: 'The Sniffer Network Analyzer', the name of the first program of its kind, developed by Network Associates, Inc. and protected by trademark. However the word 'sniffer' is now in common use, such as 'PC', and by it we refer to all programs that implement those same functions. The various sniffers can be divided into two major branches: the products that are aimed at network administrators and the internal maintenance of the networks themselves and the products developed in various information technology 'often equipped with incredible additional functions compared to commercial' tools'; both can be used as a means of accessing a network. If we want to make a previous difference that is not based only on the price of the product or its origin, we can consider the software as a whole and relate it to applications such as 'network analyzers' (network analyzer) that give the possibility to do some more operations than the simple listening and archiving of passing data on a network, such as compiling statistics on traffic and on the composition of packets. The typical functions of sniffers do not differ much and can be summarized briefly in:
conversion and filtering of data and packets into a user-readable formnetwork defect analysis, eg. because computer 'A' cannot communicate with 'B'network quality and reach analysis (performance analysis), e.g. to discover 'bottlenecks' along the networkautomated sifting of passwords and user names (in clear cipher or, more often) for subsequent analysisautomated sifting of passwords and user names (in clear text or, more often, encrypted) for subsequent analysisdetection of network intrusions through traffic log analysis
