Security, Professional (JNCIP-SEC) JN0-637 Exam Questions with Experts Answers Updated Recently

For ADVPN with OSPF, using a point-to-multipoint (p2mp) interface type and enabling dynamic-neighbors are crucial. This configuration allows dynamic discovery of neighbors and the establishment of tunnels. For more information, refer to Juniper ADVPN Configuration Guide.

In the ADVPN configuration, OSPF isn't functioning as expected due to the interface configuration on st0.0. Here are the adjustments needed:

Interface Type p2mp (Answer A): OSPF requires that the tunnel interface be set to p2mp (point-to-multipoint) to allow OSPF to communicate with multiple dynamic neighbors overthe ADVPN tunnels.

Command Example:

bash

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set interfaces st0.0 family inet ospf interface-type p2mp

Dynamic Neighbors (Answer B): The dynamic neighbors statement allows OSPF to discover and communicate with dynamically established spokes in an ADVPN environment. This is essential for ADVPN to function properly since the tunnel endpoints are not static.

Command Example:

bash

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set protocols ospf area 0.0.0.0 interface st0.0 dynamic-neighbors

These settings ensure OSPF properly functions over dynamically created ADVPN tunnels.

The Local zone represents a Layer 2 segment, which allows for traffic flows within the same zone and across other zones with proper security policies. Additionally, hosts in different zones (such as Local and Trust) can communicate when policies are defined to allow such interactions. Refer to Juniper Security Policy Documentation for detailed guidance.

From the exhibit:

IRB Interface Requirement (Answer B): To allow communication between the Trust and Untrust zones (Layer 2 and Layer 3 environments), anIRB (Integrated Routing and Bridging)interface is required. The IRB interface acts as a gateway between Layer 2 and Layer 3 domains.

Command Example:

bash

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set interfaces irb unit 0 family inet address 10.1.1.1/24

set security zones security-zone untrust interfaces irb.0

Communication Between Local and Trust (Answer D): Hosts in the Local zone (Layer 2) can communicate with hosts in the Trust zone (Layer 3) if appropriate security policies are in place. A security policy is needed to define how traffic can flow between these zones.

Command Example:

bash

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set security policies from-zone local to-zone trust policy allow-local-trust match source-address any destination-address any application any

set security policies from-zone local to-zone trust policy allow-local-trust then permit

These configurations ensure proper communication between zones in a mixed Layer 2 and Layer 3environment.

Explanation of Answer A (Session Reclassification):

APBR (Advanced Policy-Based Routing) requires the session to be classified based on the specified rule, which can change midstream as additional packets are processed. If the session was already established before the APBR rule took effect, the traffic may not be correctly reclassified to match the new APBR rule, leading to IDP (Intrusion Detection and Prevention) processing instead of being bypassed. This can occur especially when the session was already established before the rule change.

Explanation of Answer C (Application Services Bypass):

For APBR to work and bypass the IDP service, theapplication services bypassmust be explicitly configured. Without this configuration, the APBR rule may redirect the traffic, but the IDP service will still inspect and potentially drop the traffic. This is especially important for traffic destined for specific sites like social media platforms where bypassing IDP is desired.

Example configuration for bypassing IDP services:

bash

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set security forwarding-options advanced-policy-based-routing profile application-services-bypass

Step-by-Step Resolution:

Reclassify the Session Midstream:

If the traffic was already being processed before the APBR rule was applied, ensure that the session is reclassified by terminating the current session or ensuring the APBR rule is applied from the start.

Command to clear the session:

bash

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clear security flow session destination-prefix

Configure Application Services Bypass:

Ensure that the APBR rule includes the application services bypass configuration to properly bypass IDP or any other security services for traffic that should not be inspected.

Example configuration:

bash

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set security forwarding-options advanced-policy-based-routing profile application-services-bypass

Juniper Security Reference:

Session Reclassification in APBR: APBR requires reclassification of sessions in real-time to ensure midstream packets are processed by the correct rule. This is crucial when policies change dynamically or new rules are added.

Application Services Bypass in APBR: This feature ensures that security services such as IDP are bypassed for traffic that matches specific APBR rules. This is essential for applications where performance is a priority and security inspection is not necessary.

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