Free Practice Questions for Juniper JN0-232 Exam

Exception traffic is traffic that must be sent from the Packet Forwarding Engine (PFE) to the Routing Engine (RE) for processing, such as routing protocol updates, management traffic, or other control-plane packets. Because the RE is a limited and critical resource, Junos OS implementsrate limiting on exception traffic.

The purpose is toprevent denial-of-service (DoS) attacks on the Routing Engineby controlling the amount of traffic directed to it.

This ensures the RE continues to process control-plane operations reliably, even under potential attack or heavy traffic conditions.

Rate limiting does not enhance forwarding plane performance (Option A), simplify interface configuration (Option B), or manage routing protocols directly (Option D).

Security policies on SRX support several actions:

Permit:Allows traffic to pass according to the rule.

Deny:Silently drops the traffic without notifying the source.

Reject:Drops the trafficand sends a TCP RST (for TCP) or ICMP unreachable (for UDP/other protocols)back to the source. This provides feedback to the sending host.

Next-policy:Allows policy chaining to evaluate the next policy set.

Therefore, the action that causes traffic to drop and a message to be sent to the source isreject.

TheSBL (SurfControl Web Filtering)server integration is part of UTM web filtering on SRX. To confirm that the firewall is properly connected and communicating with the SBL server, the command used is:

show security web filtering status

This command displays connectivity information with the SBL server, license status, and filtering operations.

Other options:

Anti-virus (Option A) checks antivirus engine status.

Content-filtering statistics (Option C) shows local content filtering counters.

Anti-spam status (Option D) checks spam engine connectivity.

Correct Command:show security web filtering status

Security policies in Junos OS match traffic based on specific criteria:

Source and destination addresses(Option B).

Application(Option D), which may be defined as services (e.g., tcp/80) or recognized through AppID.

Other options:

MAC addresses(Option A) are not used in policy matching; policies operate at Layer 3/4.

Interface name(Option C) is used in firewall filters, not in security policy definitions.

Correct Criteria:Source address and Applications

NextGen Web Filtering (NGWF) requires SSL proxy functionality to inspect HTTPS traffic. To enable NGWF:

Option B:You can generate aself-signed certificatefor SSL proxy functionality (or import a CA-signed certificate, but the course emphasizes self-signed for lab/demo purposes).

Option D:You must configure anSSL proxy profileso that HTTPS traffic can be decrypted and inspected.

Option A:A CA-signed certificate may be used in production but is not strictly required to enable NGWF.

Option C:SSL initiation profiles are used for outbound SSL inspection initiated by the SRX, not for NGWF traffic interception.

Correct Actions:Generate a self-signed certificate, Configure an SSL proxy profile

In Juniper SRX flow-based packet processing, theflow moduleis responsible for security functions such as screening, session management, NAT, and policy enforcement. The processing order is critical:

Screens are applied before any session lookup.This ensures that packets are inspected for anomalies, floods, or protocol violations before consuming resources for session management. Examples of these screens include TCP SYN flood protection, ICMP flood protection, and port scanning protection.

After screening, thesession lookupoccurs. At this point, the firewall checks whether the packet belongs to an existing session in the session table. If a matching session is found, the packet bypasses policy evaluation and is forwarded according to the session state.

If no existing session is found, the packet continues throughroute lookup, NAT processing, and security policy evaluationbefore a new session is created.

Thus,screening occurs before the session lookup, protecting the system early in the flow process. This design ensures efficiency by dropping malicious or malformed traffic before allocating session resources.

The SRX Series devices support third-party antivirus scanning engines such asAvira. To use the Avira antivirus engine, administrators must explicitly enable the engine and ensure that the required components are properly loaded.

Enable in configuration mode:

The Avira antivirus engine must be enabled under UTM configuration mode. This step ensures the SRX device uses the Avira scanning engine for antivirus inspection.

Example:

set security utm feature-profile anti-virus avira-engine enable

Reboot the SRX device:

A system reboot is required after enabling the Avira engine to load the Avira antivirus components into memory.

Without a reboot, the Avira engine will not become active.

Why not the others?

Restarting themgdprocess (Option A) only reloads the management daemon and does not load antivirus engines.

Enabling inoperational mode(Option B) is not supported; the configuration must be applied in configuration mode.

Therefore, the correct actions to use Avira Antivirus are:Enable the Avira engine in configuration mode (Option D) and reboot the SRX device (Option C).

From the exhibit output:

Policy Information:

Policy: https-access, action-type: permit

From zone: Trust, To zone: Untrust

Application: junos-https

IP protocol: tcp, Destination port: 443

Inactivity timeout: 1800

Sequence number: 1

Analysis:

Option A:Correct. The default inactivity timeout for flow sessions is60 seconds for TCP without activity. This policy shows aninactivity timeout of 1800 seconds, which is non-default.

Option B:Incorrect. The policy shows Sequence number: 1, which means it is thefirst policy, not the second.

Option C:Correct. The policy explicitly matches application junos-https (TCP port 443) and has an action of permit. Therefore, it allows HTTPS traffic.

Option D:Incorrect. This is clearly azone-based policy, but the question asks for two correct statements. Between the four options, the explicitly correct ones are A and C.

Correct Statements:This security policy uses a non-default inactivity timeout, and this security policy permits HTTPS traffic.

Static NAT:Provides a one-to-one bidirectional mapping between internal and external IP addresses. When configured, the translation automatically applies in both directions (Option A is correct). It does not use Port Address Translation (Option C is incorrect).

Destination NAT:Allows external clients to access internal resources by translating the destination address. It supportsport forwardingso specific services (e.g., HTTP on port 80) can be forwarded to an internal host (Option D is correct). It does not require equal-sized address ranges (Option B is incorrect).

Correct Characteristics:Static NAT is bidirectional, and Destination NAT supports port forwarding.