Before adding new features, a real engineer proves the setup is correct.
STEP 27.1 — Verify trunks (VERY IMPORTANT)
On DIST-SW1:
show interfaces trunk
You should see:
- Port to HO-R1 → trunk
- Allowed VLANs → 10,20,30
STEP 27.2 — Verify VLAN membership
On HQ-SW2:
show vlan brief
PC ports should be under VLAN 10.
On HQ-SW3:
show vlan brief
- Server → VLAN 20
- Wi-Fi → VLAN 30
STEP 27.3 — Verify router subinterfaces
On HO-R1:
show run interface gi0/0.10
show run interface gi0/0.20
show run interface gi0/0.30
Look for:
- Correct VLAN tag
- Correct IP address
🔒 Why this step matters (CCNA exam mindset)
Many CCNA questions are:
“Why can’t VLAN X talk to VLAN Y?”
And the answer is almost always:
- trunk misconfig
- wrong VLAN allowed
- wrong gateway
- subinterface missing
You’re learning to diagnose, not guess.
🎯 Next high-impact topics (choose ONE)
Now you’re ready for power skills:
1️⃣ DHCP per VLAN (automatic IPs — very important)
2️⃣ ACLs between VLANs (security — CCNA loves this)
3️⃣ Replace ROAS with Layer-3 switch (CCNP foundation)
4️⃣ Break & troubleshoot the network (expert mode)
