Attacks: DoS/DDoS, VLAN hopping, MAC flooding, ARP and DNS poisoning/spoofing, rogue DHCP and APs, evil twin, on-path

To defend a network you must recognise how it is attacked. This lesson explains the network attacks named in the objectives at the level needed to spot, detect and prevent them, not to carry them out. Each one targets a specific weakness, usually a protocol that trusts whatever it hears, and each pairs naturally with a defence covered in the switch security, NAC and hardening lessons. Exam questions typically describe symptoms and ask you to name the attack, or name an attack and ask for the best mitigation.