Mix - Hard Flashcards
What is the role of the Routing Engine in Junos OS and how does it differ from the Packet Forwarding Engine?
The Routing Engine handles the Control Plane, responsible for routing decisions, protocol management, and system operations. The Packet Forwarding Engine (PFE) processes and forwards packets in the Data Plane.
In Junos OS, what command would you use to verify if the system’s configuration is valid before applying it?
You would use the command commit check to validate the configuration before committing changes.
How does Junos OS ensure the separation of Control Plane and Data Plane traffic for scalability and performance?
Junos OS uses a physically separated architecture where the Routing Engine handles the Control Plane, and the Packet Forwarding Engine handles the Data Plane, allowing for dedicated resources and higher performance.
When configuring a Junos device for dynamic routing with OSPF, what command would you use to verify OSPF neighbors?
The command show ospf neighbor will display the status of OSPF neighbors and their details.
Explain the difference between the “permit” and “deny” actions in a Junos OS firewall filter.
The “permit” action allows traffic to pass through the firewall based on the filter criteria, while the “deny” action blocks traffic that matches the filter conditions.
What is the significance of “Commit Confirm” in Junos OS and how does it help avoid configuration errors?
The commit confirm command allows administrators to apply a configuration change with a specified timeout, ensuring that if no further commits are made, the configuration will automatically revert after a defined period, reducing the risk of leaving a device in an unstable state.
How does Junos OS handle packet forwarding when multiple routing protocols have overlapping prefixes?
Junos OS uses the Longest Prefix Match (LPM) algorithm to determine the best match for a destination IP, preferring the route with the longest matching prefix.
What is the difference between a static and dynamic routing protocol in Junos OS, and when would you prefer one over the other?
Static routing requires manual configuration of routes, while dynamic routing protocols (like OSPF or BGP) automatically adjust to network changes. Static routing is preferable in stable environments with few changes, whereas dynamic routing is used in large, complex networks with frequent topology changes.
How does Junos OS handle multicast traffic and what protocol is commonly used for this?
Junos OS handles multicast traffic using protocols like IGMP (Internet Group Management Protocol) for managing group memberships and PIM (Protocol Independent Multicast) for routing multicast traffic.
What is the significance of using different security zones in Junos OS firewalls?
Security zones group interfaces based on their trust level (e.g., inside, outside), helping define and enforce policies for traffic between zones, improving security.
How do you configure a static route with a preference value in Junos OS?
You can configure a static route with a preference value using the command: set routing-options static route <destination> next-hop <next-hop> preference <value>.</value></next-hop></destination>
What is the function of the “show system uptime” command in Junos OS?
The show system uptime command displays the duration since the system was last rebooted, providing insight into the device’s stability and operational history.
How can you verify the BGP state of a neighbor in Junos OS?
Use the command show bgp neighbor <neighbor-ip> to verify the state of a BGP session and its operational status.</neighbor-ip>
What is the purpose of J-Web in Junos OS, and how does it enhance network management?
J-Web provides a graphical interface for managing and configuring Junos OS devices, allowing for easier configuration, monitoring, and troubleshooting without needing to use the command line.
When using Junos XML API, how do you fetch the routing table from a Junos device?
Using the Junos XML API, you can fetch the routing table by sending an XML request with the appropriate operation, such as <get-route-table> to retrieve routing information.</get-route-table>
How would you troubleshoot a BGP route advertisement failure in Junos OS?
To troubleshoot BGP route advertisement failures, you could use commands like show bgp summary, show bgp neighbor, and show route advertising-protocol bgp to identify misconfigurations or network issues.
What is the role of the “set security policies” command in Junos OS?
The set security policies command is used to configure firewall policies between different security zones, defining rules for allowing or blocking traffic based on source and destination criteria.
What is the default behavior of an interface in Junos OS when no IP address is configured?
By default, when no IP address is configured on an interface, it will be in an administratively down state and will not process any traffic.
How can you configure a VLAN on a Junos device and assign it to an interface?
To configure a VLAN, use the command: set vlans <vlan-name> vlan-id <vlan-id>. Then, assign it to an interface with the command: set interfaces <interface-name> unit 0 family ethernet-switching vlan members <vlan-name>.</vlan-name></interface-name></vlan-id></vlan-name>
What is the purpose of “commit check” in Junos OS?
The commit check command validates the configuration changes to ensure they are syntactically correct and do not cause conflicts or errors before committing them.
