Troubleshooting Methods Flashcards

How do you verify that a firewall filter is working correctly in Junos?

Answer: show firewall filter FILTER-NAME and show firewall log to check counter increments and logged packets

Verifying a firewall filter involves checking 'show firewall filter [name]' for term counter increments and 'show firewall log' for packets matched by terms with the 'log' action.

What information does 'show system processes extensive' provide in Junos?

Answer: CPU and memory utilization for all running Junos daemons and system processes

'show system processes extensive' displays a real-time process table similar to Unix 'top', showing CPU%, memory usage, PID, and state for every Junos daemon and system process.

In Junos, what command verifies whether a specific prefix is in the routing table?

Answer: show route [prefix] exact

'show route [prefix] exact' checks for an exact match of the specified prefix in the routing table, showing its protocol, next-hop, and metric without returning longer/shorter matches.

What is the Junos command to check the status of all OSPF adjacencies?

Answer: show ospf neighbor

'show ospf neighbor' in Junos operational mode displays all OSPF neighbors, their state (Full, 2-Way, ExStart, etc.), dead interval timer, and interface.

When a BGP session is stuck in 'Active' state in Junos, what is the most likely cause?

Answer: The router cannot establish a TCP connection to the BGP peer (connectivity, ACL, or wrong peer address)

BGP 'Active' state means the router is attempting to initiate a TCP connection but has not succeeded, typically due to connectivity failure, wrong peer IP, ACL blocking port 179, or the peer not being configured.

What does the 'show chassis hardware' command display in Junos?

Answer: Physical hardware inventory including FPCs, PICs, Routing Engines, and serial numbers

'show chassis hardware' provides a complete inventory of all installed hardware components with their descriptions, part numbers, and serial numbers, useful for inventory and RMA purposes.