40 Explain the purpose of network scanners
What are Packet Sniffers?
The term packet sniffer also refers to protocol analyzer or packet analyzer. Packet sniffers are used to monitor various packets that travel through the network. They run either on computers or they require dedicated hardware devices. There are various packet sniffers available in the market for example Wireshark, HP Open view etc.
Figure 67: Wireshark
This is the working snapshot of wire sharp packet analyzer. It captures the packets leaving or entering the interface which we want to monitor and displays the output for testing, monitoring etc.
Describe port scanners
Port scanner is the software that checks the ports on the system and displays their states. This is an important tool that is used to scan open ports on the system that might provide security risk as an open port can be used by unauthorized users to enter into the network.
Examples of port scanners are NMAP, Angry IP scanner etc. NMAP works on the UNIX systems.
Figure 68: Port Scanner