LLDPMon

Short for LLDP monitoring, LLDPMon provides a command line application that can identify LLDP packets sent throughout Ethernet networks, thus making it easier for network administrators to determine the switches and port numbers each device is connected to.

Please be advised that LLDPMon requires a recent version of Npcap installed on the local system, as it uses its capabilities to find network adapters and listen for LLDP (Link Layer Discovery Protocol) packets. 

LLDPMon can help you determine a network’s topology and find potential connectivity issues, which is surely helpful in larger, more complex networks with a significant number of devices.

For LLDPMon to work properly, the switch or networking device must support LLDP. Should LLDP not be enabled on all the ports, LLDPMon will not be able to pick up any packets or display any information.

Running LLDPMon in the command console allows it to find the available network adapters and prompts you to specify the interface to monitor. The application works on Ethernet networks only, actively listening for LLDP packets. To stop it from listening, simply hit the CTRL + C combination while the window is in focus.

Running LLDPMon with no parameters displays the system name and description, the management addresses, the port interface name and its description. Using the “/detail” parameter displays all the information that the network device advertises in the LLDP packet. Using the “/capture  ” parameter, you can easily save the LLDP packet to file.