LLDPMon is a network monitoring tool that operates by listening for LLDP (Link Layer Discovery Protocol) packets transmitted over Ethernet connections. These packets are used to exchange information about network devices, such as their identity, capabilities, and network connectivity status.

LLDPMon captures and displays this information, allowing you to view a detailed map of your network topology and enabling you to identify potential issues or misconfigurations. LLDPMon can be particularly useful in large, complex networks, where keeping track of all network devices and their connections can be challenging.

It is important to note that LLDPMon can only detect LLDP packets if your switch or networking device supports LLDP and it is enabled on all ports. If this is not the case, LLDPMon will not pick up any packets or display any information.

Here's how to use LLDPMon: First, make sure that you have installed the latest version of Npcap. You can download Npcap from https://npcap.com. Once you have installed Npcap, run LLDPMon and select the network interface you want to listen to. To stop LLDPMon from listening, press CTRL + C.

LLDPMon syntax:

LLDPMon.exe
With no parameters, the information displayed includes the system name, system description, management address(es), port description, and port ID interface name (if available).

LLDPMon.exe /detail
This displays all information the switch/networking device advertises within the LLDP packet.

LLDPMon.exe /capture
This saves the LLDP packet to a file. If you see unknown TLV messages displayed, you can then email the .pcap file to PacketCatcher@outlook.com to include in a future release.

  Download