LAN of overbearing control ARP deception of experience-vulnerability warning-the black bar safety net

ARP spoofing I believe we are not familiar with it, but someone know the cheat of this 2 words real meaning? Oh, that ARP spoofing hair is some kind of ARP packet? ARP spoofing how to prevent? ARP spoofing on my door what useful value? ARP spoofing on my door what harm? Okay and we talk about it...