Network Troubleshooting & Tools Flashcards

A user reports intermittent connectivity drops every few minutes. Which tool would BEST help identify whether the issue is packet loss or latency spikes?

Answer: ping with extended count

Running ping with a high count (e.g., ping -n 100) over time reveals packet loss percentages and latency variations.

Which command displays the current ARP cache on a Windows system?

Answer: arp -a

The arp -a command displays all current ARP cache entries mapping IP addresses to MAC addresses.

A technician uses traceroute and sees that hop 5 shows '* * *' but hop 6 responds normally. What does this most likely indicate?

Answer: Hop 5 blocks ICMP/UDP but forwards traffic

A router can be configured to drop ICMP TTL-exceeded messages while still forwarding traffic normally, causing asterisks in traceroute output.

Which Cisco IOS command shows the status of all interfaces including IP addresses and line/protocol state?

Answer: show ip interface brief

The 'show ip interface brief' command provides a concise summary of all interfaces with their IP address, status, and protocol state.

A workstation can ping its default gateway but cannot reach the internet. What should the technician check NEXT?

Answer: Verify the default gateway's routing table and WAN connectivity

Since the gateway is reachable, the issue is likely upstream — the gateway's WAN link or routing table should be checked next.

What does the output 'Request timed out' from a Windows ping command indicate?

Answer: The destination did not respond within the timeout period

'Request timed out' means the ICMP echo reply was not received within the default timeout, indicating the host may be unreachable or blocking ICMP.

Which tool captures packets on a network interface for deep protocol analysis?

Answer: Wireshark

Wireshark is a packet capture and protocol analysis tool that records all traffic on a network interface for detailed inspection.