NE NE Network Troubleshooting 2

Question 1

What does the command 'show interface' reveal that helps diagnose an interface problem?

Accepted Answer

Line status, protocol status, error counters, and traffic statistics

Answer

'Show interface' reports line protocol state, input/output errors, drops, CRC errors, and collisions — essential for diagnosing physical and data-link issues.

Question 2

A network engineer sees 'interface is up, line protocol is down' on a serial interface. What does this indicate?

Accepted Answer

Physical connectivity exists but the data link layer is not functioning (e.g., encapsulation mismatch)

Answer

Up/down means the physical signal is present (cable connected) but keepalives or LCP negotiation are failing — typically an encapsulation mismatch or clocking issue.

Question 3

Which command shows the current ARP cache on a Cisco router?

Accepted Answer

show arp

Answer

'Show arp' displays the router's ARP table mapping IP addresses to MAC addresses for connected interfaces and resolved next-hops.

Question 4

What is the most effective first step when troubleshooting a reported network outage?

Accepted Answer

Define and document the problem by gathering information from affected users and systems

Answer

Effective troubleshooting begins with defining the problem — understanding scope, symptoms, and recent changes before making any modifications.

Question 5

A network engineer suspects an MTU mismatch is causing packet fragmentation issues. Which command helps verify the MTU on a Cisco interface?

Accepted Answer

show interface [name]

Answer

'Show interface' displays the MTU configured on an interface; mismatched MTUs on adjacent routers cause fragmentation or dropped oversized packets.

NE - Network Engineer Practice Test

NE - Network Engineer Practice Test

NE NE Network Troubleshooting 2