JN0-105 Exam Dumps - Junos - Associate (JNCIA-Junos) 2024 Exam

At the operational mode prompt on a Junos device, you can use various commands to view the device's status and request system operations. The show interface ge-0/0/0 command is used to display information about a specific interface, while the request system shutdown command is used to properly shut down the device. The set command is used in configuration mode, not operational mode, and the run command is used to execute operational mode commands from configuration mode.

Firewall filters in Junos OS are stateless, meaning they process each packet individually without regard to the state of a connection or sequence of packets. These filters can match various packet attributes, including those at Layer 4, such as TCP and UDP port numbers. This allows for granular control over traffic based on the type of service or application. Unlike stateless filters, stateful firewalls keep track of the state of active connections and make decisions based on the context of the traffic flow, which is not a capability of Junos firewall filters. Additionally, Junos firewall filters primarily operate up to Layer 4 and do not natively inspect Layer 7 parameters, which involve application-level data.

One of the key advantages of Junos OS is its ability to roll back to previous configurations. This feature allows administrators to revert to an earlier configuration state, which is invaluable for quickly recovering from configuration errors or undesired changes. Junos OS maintains an archive of previous configurations, enabling easy rollback to any saved state. Another significant advantage of Junos OS is its modular design. The operating system is structured so that different processes and services run in separate protected memory spaces, enhancing the stability and reliability of the system. If one process fails, it does not affect the others, thereby minimizing the risk of system-wide failures.

Class of Service (CoS) in Junos OS provides tools for managing traffic congestion and ensuring that latency-sensitive traffic is given priority over less time-critical data. By implementing CoS, network administrators can classify traffic into different priority levels, apply scheduling policies to ensure that high-priority traffic is transmitted first, and use congestion management techniques such as queue buffers and drop profiles. This helps in maintaining the quality of service for critical applications, especially during periods of high network congestion. However, CoS does not eliminate congestion entirely nor does it inherently make the network faster; it provides a mechanism for better managing and controlling traffic flows according to their importance and time sensitivity.

The show route table inet6.0 command displays all IPv6 routes in the default routing instance. In Junos OS, the routing table for IPv6 addresses is referred to as inet6.0, whereas inet.0 is used for IPv4 unicast routes. The other options do not correspond to the correct IPv6 routing table.

References:

Juniper official documentation: Junos OS Routing Tables Overview.

If you've committed a configuration and then need to revert to the previous configuration, the rollback command is used. Since the incorrect IP address has not been committed, as indicated by the commit check command being successful, issuing rollback 1 will undo the changes made in the current session, which includes the accidental entry of the IP address.

The show | compare command in Junos OS is used to display the differences between the candidate configuration and the active configuration. If no output is shown when you issue this command, it means that there are no changes between the candidate configuration and the active configuration. This indicates that the candidate configuration is identical to the active configuration, and thus no differences are displayed.

To advertise a default static route into OSPF on router R1, a routing policy should be configured. This policy would typically include a statement to match the default route (0.0.0.0/0) and then apply an action to set the route as an OSPF external type, which would then be redistributed into the OSPF domain. The routing policy is a set of conditions and actions that determine how routes are imported into or exported from the routing table and how routes are shared between routing instances or routing protocols. After defining the policy, it must be applied to OSPF under the export section of the OSPF configuration on R1. This process will allow R1 to announce the default route to other OSPF routers in the network, which then can use it as a gateway of last resort to reach the Internet or other networks not explicitly known to the OSPF domain.