Paloalto Networks PCNSE Exam Dumps Questions and Answers

To address the issue of application performance degradation due to excessive VoIP traffic, the administrator should configure QoS on the egress interface for the traffic flows and a QoS profile defining traffic classes. QoS stands for Quality of Service, which is a feature that allows the firewall to manage bandwidth usage and prioritize traffic based on various criteria, such as application, user, service, etc. QoS can help improve the performance and quality of latency-sensitive applications, such as VoIP, by guaranteeing them sufficient bandwidth and priority over other traffic1.

To enable QoS on the firewall, the administrator needs to create a QoS profile and a QoS policy. A QoS profile defines the eight classes of service that traffic can receive, including priority, guaranteed bandwidth, maximum bandwidth, and weight. A QoS policy identifies the traffic that matches a specific class of service based on source and destination zones, addresses, users, applications, services, etc2. The administrator can also create a custom QoS profile or use the default one.

The administrator should apply QoS on the egress interface for the traffic flows, which is the interface where the traffic leaves the firewall. This is because QoS can only shape outbound traffic and not inbound traffic. The egress interface can be either internal or external, depending on the direction of the VoIP traffic. For example, if the VoIP traffic is from internal users to external servers, then the egress interface is the untrust interface facing the ISP. If the VoIP traffic is from external users to internal servers, then the egress interface is the trust interface facing the LAN3.

The administrator should assign a high priority and a sufficient guaranteed bandwidth to the VoIP traffic in the QoS profile. This will ensure that the VoIP packets are processed first by the firewall and are not dropped or delayed due to congestion. The administrator can also limit or block other applications that consume too much bandwidth or pose security risks in the same or different QoS classes4.

An Application Override policy for SIP traffic is not necessary to address this issue. An Application Override policy is used to change or customize the App-ID of certain traffic based on port and protocol criteria. This can be useful for optimizing performance or security for some applications that are difficult to identify or have non-standard behaviors. However, SIP is a predefined App-ID that identifies Session Initiation Protocol (SIP) traffic, which is commonly used for VoIP signaling. The firewall can recognize SIP traffic without an Application Override policy5.

QoS on the ingress interface for the traffic flows is not effective to address this issue. As mentioned earlier, QoS can only shape outbound traffic and not inbound traffic. Applying QoS on the ingress interface will not have any impact on how the firewall handles or prioritizes the incoming packets6.

A QoS policy for each application is not required to address this issue. A QoS policy can match multiple applications in a single rule by using application filters or application groups. This can simplify and consolidate the QoS policy configuration and management. The administrator does not need to create a separate QoS policy for each application unless there is a specific need to assign different classes of service or parameters to each application7.

References: QoS Overview, Configure QoS, QoS Use Cases, QoS Best Practices, Application Override, QoS FAQ, Create a QoS Policy Rule

When sizing a decryption firewall deployment, two factors that should be considered are the encryption algorithm and the TLS protocol version. These factors affect the amount of resources and processing power that the firewall needs to decrypt and inspect SSL/TLS traffic.

The encryption algorithm is the method that the server and the client use to encrypt and decrypt the data exchanged in an SSL/TLS session. Different encryption algorithms have different levels of security and performance. For example, AES is a symmetric encryption algorithm that is faster and more efficient than RSA, which is an asymmetric encryption algorithm. However, RSA is more secure than AES because it uses public and private keys to encrypt and decrypt data, while AES uses a single shared key. The firewall must support the encryption algorithms that are used by the servers and clients that it decrypts, and it must have enough CPU and memory resources to handle the decryption workload12.

The TLS protocol version is the standard that defines how the server and the client establish and maintain an SSL/TLS session. Different TLS protocol versions have different features and requirements for encryption algorithms, cipher suites, certificates, handshake messages, etc. For example, TLS 1.3 is the latest and most secure version of TLS, which supports only strong encryption algorithms and cipher suites, such as AES-GCM and ChaCha20-Poly1305, and requires elliptic curve certificates. The firewall must support the TLS protocol versions that are used by the servers and clients that it decrypts, and it must have enough hardware acceleration resources to handle the decryption speed34.

The number of security zones in decryption policies and the number of blocked sessions are not relevant factors for sizing a decryption firewall deployment. The number of security zones in decryption policies only affects how the firewall matches traffic to decryption rules based on source and destination zones, but it does not affect the decryption performance or resource consumption. The number of blocked sessions only indicates how many sessions are denied by the firewall based on security policy or decryption policy rules, but it does not affect the decryption capacity or throughput56.

References: Encryption Algorithms, TLS Protocol Versions, Decryption Policy, PCNSE Study Guide (page 60)

To enable the firewall team to view and select from a list of usernames and user groups directly within Panorama policies for new security rule creation, User-ID group mapping should be configured in Panorama under User Identification. This feature allows Panorama to collect user and group information from various sources (like Active Directory) and use this information to create policies. By setting up User-ID group mapping, administrators can leverage user identity as criteria in security rules, enabling more granular access control and policy enforcement based on user or group membership, thereby enhancing the overall security posture.