Disable DTP and set trunking manually.
Layer 2 security is invisible when done right. But when it's missing, the whole network crumbles. What other Layer 2 attacks worry you most—CDP/LLDP recon, STP manipulation, or ARP poisoning? Drop a comment below. 14.9.11 packet tracer - layer 2 vlan security
Take the time to run this lab. Break it on purpose. Watch the show port-security , show dhcp snooping binding , and show interfaces status err-disabled outputs. Disable DTP and set trunking manually
That’s where comes in. It’s the often-overlooked foundation of network defense. What other Layer 2 attacks worry you most—CDP/LLDP
On the access ports connecting to end devices (Fa0/1, Fa0/2, etc.), you need to lock down the MAC addresses.
interface range fa0/1-24 switchport mode access switchport nonegotiate On the actual trunk between switches:
Let’s break down what this lab teaches and why it matters in the real world. Imagine you are responsible for a corporate network. Users are in VLAN 10 (Employees) and VLAN 20 (Guests). The lab presents a simple topology: one multilayer switch (distribution), one layer 2 switch (access), and a few PCs.