JN0-335 Exam Dumps : Security, Specialist (JNCIS-SEC)

Statistical sampling is a technique that reduces the amount of flow data that is sent to JSA by sampling a subset of packets from the network device. Statistical sampling can help reduce network bandwidth and storage requirements, but it also increases processor utilization on the network device and decreases event correlation accuracy on JSA. Statistical sampling can also affect the accuracy of reports and searches that are based on flow data. Therefore, it is recommended to use statistical sampling only when necessary and with caution12.

BGP FlowSpec is not used to collect traffic flows from Junos OS devices, but to distribute firewall filter rules to routers that participate in BGP. BGP FlowSpec can help mitigate distributed denial-of-service (DDoS) attacks by filtering unwanted traffic based on flow attributes such as source and destination IP addresses, ports, and protocols3.

Superflows are not a method of collecting network traffic flows, but a way of grouping individual flows that match certain criteria into a single record. Superflows can help detect common attack vectors and reduce the number of flows that are stored on JSA. Superflows do not reduce traffic licensing requirements, but they can help optimize the performance and storage of JSA4. References:

• 1: Flow Sources | JSA 7.5.0 | Juniper Networks
• 2: JSA Events and Flows | JSA 7.5.0 | Juniper Networks
• 3: Understanding BGP FlowSpec
• 4: Superflows | JSA 7.5.0 | Juniper Networks

 The error occurred because the “http” application is not defined in this context of Juniper SRX Series device configuration. One solution is to create a custom application named “http” at the [edit applications] hierarchy level (Option C). Another solution is to modify the security policy to use the built-in “junos-http” application which is predefined and doesn’t need an explicit definition (Option D). Options A and B are not correct because they do not address the root cause of the error, which is the undefined application “http”. References: The answers can be verified from Juniper’s official documentation on security policies and applications available on their website. Here are some relevant links:

• Security Policies Feature Guide for Security Devices
• Understanding Applications and Application Sets for SRX Series Devices
• Configuring Custom Applications for SRX Series Devices
• Predefined Applications for SRX Series Devices