What is the reason for the abnormal connection of the network and the normal external network?
The abnormal consideration of the external network connection is ARP attack. In order to solve the ARP attack, 802.1x protocol can be configured on the switch in the network.
ARP attack is to spoof ARP by forgery IP address and MAC address, which can generate a large number of ARP traffic in the network to block the network. As long as the attacker continuously sends out fake ARP response package, the attacker can change the IP MAC entry in the ARP cache of the target host, causing the network break or intermediate attack.
ARP attack mainly exists in the LAN network. If a computer infects the ARP Trojan horse in the LAN, the system infected with the ARP Trojan horse will try to intercept the communication information of other computers in the network by means of "ARP spoofing", and thus cause communication failure of other computers in the network.