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

Unified policies are security policies that enable you to use dynamic applications as match conditions along with the existing 5-tuple or 6-tuple (with user firewall) match conditions to detect application changes over time3 If the traffic matches the security policy rule, one or more actions defined in the policy are applied to the traffic3 During the initial policy lookup phase, which occurs prior to a dynamic application being identified, if there are multiple policies in the potential policy list, the SRX Series Firewall applies the default security policy until a more explicit match has occurred2 The policy that best matches the application is the final policy2 APPID results are used to determine the final security policy1 References:

• 1: Unified Security Policies | Junos OS | Juniper Networks
• 2: Unified Policies Support for Flow | Junos OS | Juniper Networks
• 3: Unified Policy Overview - TechLibrary - Juniper Networks

 SSL proxy is a transparent proxy that performs SSL encryption and decryption between the client and the server. It allows inspection of encrypted traffic by terminating the SSL connection from either end and applying security policies to the clear text. SSL proxy can leverage pre-match or post-match results to determine whether to apply SSL proxy to a session. Pre-match results are based on the initial packet of the session, while post-match results are based on the application identification after the session is established. In the exhibit, the session shows that the application services identification is “ssl-proxy”, which means that SSL proxy is applied based on the pre-match results. The cache lookup status for application services is “on”, which means that the SRX Series device uses the application system cache to store the pre-match results for faster processing. Therefore, the correct answer is D. SSL proxy leverages pre-match result. References: = SSL Proxy, Configuring SSL Proxy, and Application System Cache

• A stateful firewall in SRX Series devices keeps track of the state of network connections, distinguishing legitimate packets for different types of connections and allowing only packets that match a known active connection. Sessions are created when a TCP SYN packet is received and permitted by the security policy1.
• A security policy is a set of rules that defines how traffic is processed by the SRX Series device. A security policy applies the security rules to the transit traffic within a context (from-zone to to-zone) and each policy is uniquely identified by its name. The traffic is classified by matching the source and destination zones, the source and destination addresses, and the application that the traffic carries in its protocol headers with the policy database in the data plane2.
• A Layer 3 route is a path that a packet takes to reach its destination based on the destination IP address. The SRX Series device performs a longest-match Layer 3 route table lookup to determine the next hop for the packet3.
• An Application Layer Gateway (ALG) is a software component that provides application-level awareness, security, and control for specific protocols. An ALG inspects the application-layer payload of a packet and modifies it if necessary to allow the application to traverse the SRX Series device. For example, an ALG can rewrite IP addresses and port numbers in the payload of FTP or SIP packets4.
• The sequence that an SRX Series device uses when implementing stateful session security policies using Layer 3 routes is as follows3:

References:

• 1: Traffic Processing on SRX Series Firewalls Overview | Junos OS | Juniper Networks
• 2: Best Practices for Defining Policies on High-End SRX Series Devices - TechLibrary - Juniper Networks
• 3: [SRX] Example: Configuring TCP SYN Check options on a per-policy basis
• 4: Application Layer Gateways Overview | Junos OS | Juniper Networks