Silently monitoring using ARP Spoof
If you don’t want to buy additional device and change your network topology, IMMonitor provides an arp-spoof tool to help you. However, we recommend you use a port mirror switch for long term use because arp-spoof will has some shortcomings:
Always do not spoof more than 30 computers and keep your computer stable. If your computer hangs or power off when spoofing, the computers being spoofed will lose connections.
Run ARP Spoof from IMMonitor
You need to restart your computer for the first time running arp-spoof. After restart, run arp-spoof again, choose your adaptor and set the mode to “Full duplex”, check the computers you want to spoof and click “Start ARP Spoof”.