The replies in the thread reported using sysctl to change kernel state. How could you figure this out if you didn't know the appropriate variable to change?
First, use grep with sysctl to see if any variables involve ARP:
bash-2.05b$ sysctl -a | grep -i arp
These look interesting. What do they mean?
bash-2.05b$ sysctl -d net.link.ether.inet.log_arp_wrong_iface
net.link.ether.inet.log_arp_wrong_iface: log arp packets arriving on the wrong interface
bash-2.05b$ sysctl -d net.link.ether.inet.log_arp_movements
net.link.ether.inet.log_arp_movements: log arp replies from MACs different
than the one in the cache
We can disable either of these variables using syntax like the following:
bash-2.05b$ sudo sysctl net.link.ether.inet.log_arp_wrong_iface=0
net.link.ether.inet.log_arp_wrong_iface: 1 -> 0
You can set it back to the default by setting the value=1. To make this a permanent change, make the following entry in the /boot/loader.conf: