Changed PCNSE Exam Questions

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.

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

The table displays NAT rules configured on the firewall. The key points are:

Source Zone and Destination Zone define the traffic flow.

Source Address and Destination Address specify the IP addresses involved.

Service indicates the type of traffic (e.g., any, ping).

Source Translation and Destination Translation show the translated IP addresses for NAT.

Issue and Resolution Options

The application server at 192.168.197.40 can establish outbound connections but faces issues with inbound connections due to the shared NAT IP 198.51.100.88. The external database server cannot establish a secure connection back to 192.168.197.40.

Options to Resolve the Issue:

Replace the Two NAT Rules with a Single Rule:

Combining both DMZ servers into one NAT rule might simplify configuration but could cause issues in distinguishing inbound traffic for each server.

Pros: Simplifies rule management.

Cons: Might not address the inbound traffic issue properly.

New Public IP Address:

Obtaining a new public IP address for the new server (192.168.197.40) ensures dedicated inbound and outbound NAT.

Pros: Clear separation of traffic, resolves inbound connectivity issues.

Cons: Requires additional public IP.

Separate Source NAT and Destination NAT Rules:

Configuring distinct NAT rules for source and destination addresses without using the bidirectional option.

Pros: Clear and distinct rules for each direction of traffic.

Cons: More complex to manage, might require more firewall resources.

Move the NAT Rule:

Adjusting the order of NAT rules to prioritize the new server’s rule.

Pros: Simple reordering might resolve prioritization conflicts.

Cons: Might not fully resolve the inbound connection issue.

When a firewall’s local configuration overrides a Panorama template, Panorama detects this discrepancy and marks the template as out of sync (Option A) in the UI (e.g., under Templates > Device status). This alerts administrators to resolve the conflict.

Option B (only Panorama reverts) is false; local commits can revert. Option C (not visible) is incorrect; sync status is visible. Option D (update template) doesn’t occur automatically. Documentation explains this sync behavior.