Configure a sniffing interface to monitor for example a SPAN (mirror) port.

• Configure enp2s0 as sniffing interface, edit /etc/network/interfaces.d/enp2s0.conf

  allow-hotplug enp2s0
  iface enp2s0 inet manual
    offload-tx  off
    offload-rx  off
    offload-sg  off
    offload-tso off
    pre-up sysctl -w net.ipv6.conf.enp2s0.autoconf=0
    pre-up sysctl -w net.ipv6.conf.enp2s0.accept_ra=0
    pre-up ifconfig $IFACE promisc -arp up
    post-down ifconfig $IFACE down