Packet Tracer’s simulation mode revealed the truth: red packets dropping at the trunk port, rejected like a bouncer checking an expired ID.

“I need a trunk,” Alex whispered.

Alex learned the hard lesson: deleting a VLAN from one switch doesn’t delete it from others. But it does break connectivity for any access port still assigned to that missing VLAN on that switch.

“Perfect isolation,” Alex said, closing Packet Tracer. “Almost as good as my weekend plans.”

interface fastEthernet 0/1 switchport mode access switchport access vlan 10 exit interface fastEthernet 0/2 switchport mode access switchport access vlan 20 F0/3 → VLAN 30. F0/4 → VLAN 10. And so on.

“Allowed VLANs,” Alex muttered. “Add 30.”

“Right,” Alex groaned. “The switch doesn’t know which PC belongs to which VLAN. It’s like a hotel front desk that doesn’t ask for your room key.” Back on S1:

3.3.12 Packet Tracer - Vlan Configuration.pka Official

Packet Tracer’s simulation mode revealed the truth: red packets dropping at the trunk port, rejected like a bouncer checking an expired ID.

“I need a trunk,” Alex whispered.

Alex learned the hard lesson: deleting a VLAN from one switch doesn’t delete it from others. But it does break connectivity for any access port still assigned to that missing VLAN on that switch. 3.3.12 packet tracer - vlan configuration.pka

“Perfect isolation,” Alex said, closing Packet Tracer. “Almost as good as my weekend plans.” Packet Tracer’s simulation mode revealed the truth: red

“Allowed VLANs,” Alex muttered. “Add 30.”

“Right,” Alex groaned. “The switch doesn’t know which PC belongs to which VLAN. It’s like a hotel front desk that doesn’t ask for your room key.” Back on S1: