LAN scanner with PRTG

The Port v2 sensor monitors a network service by connecting to one or more of its TCP/IP ports. It can show the following:

• Number of open and closed ports
• Number of errors
• Maximum time until a request to connect to a port was accepted

The SNMP Traffic v2 sensor monitors bandwidth and traffic on a device. It can show the following:

• Number of incoming and outgoing broadcast, multicast, unicast, and non-unicast packets
• Number of incoming and outgoing discards and errors
• Total, incoming, and outgoing traffic
• Number of incoming, unknown protocols

A LAN scanner is a tool or software like PRTG Network Monitor used to scan and analyze devices and resources on a Local Area Network (LAN). It helps users identify all the devices that are connected to the network, as well as gather information about them, such as their IP addresses, MAC addresses, open ports, and device types. LAN scanners are often used by network administrators and security professionals for monitoring, troubleshooting, and securing the network.

Key functions of a LAN scanner include:

• Device discovery: It detects all devices connected to the LAN, including computers, printers, smartphones, and servers.
• IP scanning and identification: It provides details about the IP addresses (IPv4, IPv6) and MAC addresses of each device.
• Port scanning: As a port scanner, it checks for open or active ports on devices, which can reveal which services are running on a specific machine (e.g., HTTP, FTP, or SSH).
• Network troubleshooting: It helps diagnose network problems by identifying unreachable or malfunctioning devices.
• Security auditing: It can be used to identify potential vulnerabilities, like open ports or unauthorized devices, which might be exploited by attackers.
• Real-time monitoring: Some LAN scanners provide real-time monitoring of network activity, showing when devices join or leave the network.

The key difference between a LAN sniffer and a LAN scanner lies in their functions and how they interact with the network:

LAN scanner (also known as a network scanner or IP scanner)

A LAN scanner is used to discover and gather information about devices on a Local Area Network (LAN), such as their IP addresses, MAC addresses, open ports, and the services they are running. It actively probes the network by sending out requests (e.g., ping requests, ARP requests) to find devices and determine their status or characteristics.

LAN sniffer (also known as a network sniffer or packet sniffer)

A LAN sniffer is used to capture and analyze data packets that travel over the network. It monitors the traffic between devices, allowing you to inspect the content of network communication in real-time. It passively listens to the network by capturing all data packets that are broadcast over the network, without necessarily interacting with the devices themselves. It provides detailed information about the packets' contents, such as source and destination IPs, protocols used (e.g., HTTP, FTP), and even the actual data being transmitted (if not encrypted).

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, for example the traffic of a switch port, the CPU load of a server, or the free space on a disk drive.

On average, you need about 5-10 sensors per device or one sensor per switch port.