Sniffers are a software/hardware tool that allows network packets to be captured, interpreted and stored for later analysis.
The use of a sniffer includes these activities:
Acquisition of data packets
Traffic logging and analysis
Decrypting packets
Network troubleshooting
Checking firewalls
Maintaining a smooth traffic flow
How does a sniffer work?
First of all, here is some basic information about 'traffic'. Just as cars (carrying people) make up the traditional traffic circulating on the street, Internet traffic is made up of packets (carrying data) travelling over a network. If you are at home, you probably ignore most of the cars that pass by, but if a truck parks in front of your house, you might want to check who is in it. Similarly, the computer ignores most of the traffic travelling on the network and only examines the specific data packets it receives directly. Sniffers are a kind of toll booth and have the function of examining all cars passing on the street, not just those parked in front of a driveway. Unfiltered sniffers check every car, i.e. they collect all traffic travelling through a network. Filtered sniffers can be configured to examine only certain types of traffic, intercepting suspicious traffic to check its content.
There are several free or inexpensive sniffing tools available online, such as Wireshark and CloudShark: if you are not able to implement one of these solutions yourself, ask your IT consultant or contact our support.