Speak Clearly

Interview Answer Bank: Skill → Lab → Story

Each answer must connect theory to a lab I actually built or a ticket I actually fixed. No empty textbook chanting.

# Answer Template

PartWhat to write
Simple answerOne or two plain sentences.
Lab proofWhich lab or ticket proved it.
Commands usedThe exact commands used to verify.
Mistake learnedOne failure and how it was fixed.
Professional answerThe final clean interview version.

# Core Questions

Explain DNS

  • Simple: DNS converts names into IP addresses.
  • Proof: DNS failure ticket, nslookup, browser by IP vs name.
  • Interview: I check DNS by testing IP reachability first, then name resolution.

Explain DHCP

  • Simple: DHCP automatically gives IP settings to clients.
  • Proof: APIPA ticket, DHCP scope check, renew/release.
  • Commands: ipconfig /all, ipconfig /renew.

Explain VLAN

  • Simple: A VLAN separates one switch into logical networks.
  • Proof: HR and IT VLAN lab.
  • Commands: show vlan brief, access port config.

Explain Trunking

  • Simple: A trunk carries multiple VLANs between switches.
  • Proof: Missing VLAN on trunk ticket.
  • Commands: show interfaces trunk.

Explain STP

  • Simple: STP prevents Layer 2 loops.
  • Proof: root bridge and blocked port lab.
  • Commands: show spanning-tree.

Explain OSPF

  • Simple: OSPF is a dynamic routing protocol that shares route information inside an organization.
  • Proof: multi-router OSPF lab.
  • Commands: show ip ospf neighbor, show ip route ospf.

Explain NAT

  • Simple: NAT translates private IP addresses to public or shared addresses.
  • Proof: PAT internet simulation lab.
  • Commands: show ip nat translations.

Explain ACL

  • Simple: ACLs permit or deny traffic based on source, destination and port.
  • Proof: standard vs extended ACL lab.
  • Rule: always remember implicit deny and direction.

Troubleshoot No Internet

  • Check link, IP, gateway, DNS, route, firewall, external reachability.
  • Use ping gateway, ping 8.8.8.8, nslookup, traceroute.
  • Document root cause and verification.

# Weekly Rule

After every lab: add one interview answer. If I cannot explain the lab in simple words, the lab is not finished.