Juniper Juniper Certifications JN0-637 Questions & Answers

• Question 51:

  You want to create a connection for communication between tenant systems without using physical revenue ports on the SRX Series device.

  What are two ways to accomplish this task? (Choose two.)

  A. Use an external router.

  B. Use an interconnect VPLS switch.

  C. Use a secure wire.

  D. Use a point-to-point logical tunnel.

  Correct Answer: CD

  Secure wire and logical tunnels provide internal connectivity options for isolated tenant systems within an SRX device, avoiding the need for physical interfaces. Secure wire maintains security context, while logical tunnels facilitate inter-system communication. More on this can be found at Juniper Tenant Systems Documentation. To create a connection between tenant systems without using physical interfaces on an SRX Series device, you have two effective options: Secure Wire (Answer C): This feature allows you to create a secure, internal connection between security zones. Essentially, traffic is bridged between two zones without needing to pass through physical interfaces, providing a "virtual" wire. Configuration Example: bash Copy code set security zones security-zone zone1 interfaces ge-0/0/0.0 host-inbound-traffic system-services all set security zones security-zone zone2 interfaces ge-0/0/1.0 host-inbound-traffic system-services all set security secure-wire secure-wire1 from-zone zone1 to-zone zone2 Point-to-Point Logical Tunnel (Answer D): This establishes a virtual connection between two different points (zones or systems) within the SRX device using logical interfaces like lt (logical tunnel interfaces). No physical ports are required, and it's useful for connecting isolated tenant systems. Configuration Example: bash Copy code set interfaces lt-0/0/0 unit 0 family inet address 192.168.1.1/30 set interfaces lt-0/0/1 unit 0 family inet address 192.168.1.2/30 set security zones security-zone zone1 interfaces lt-0/0/0.0 set security zones security-zone zone2 interfaces lt-0/0/1.0 Both methods are suitable for connecting systems within the SRX without using physical interfaces.

• Question 52:

  You are asked to connect two hosts that are directly connected to an SRX Series device. The traffic should flow unchanged as it passes through the SRX, and routing or switch lookups should not be performed. However, the traffic should still be subjected to security policy checks.

  What will provide this functionality?

  A. MACsec

  B. Mixed mode

  C. Secure wire

  D. Transparent mode

  Correct Answer: C

  Secure wire mode on SRX devices allows traffic to flow transparently through the firewall without being routed or switched, while still applying security policies. This is ideal for scenarios wheretraffic inspection is required without altering the traffic path or performing additional routing decisions. For further details on Secure Wire, refer to Juniper Secure Wire Documentation.

  In this scenario, you want traffic to pass through the SRX unchanged (without routing or switching lookups) but still be subject to security policy checks. The best solution for this requirement is Secure Wire .

  of Answer C (Secure Wire):

  Secure Wireallows traffic to flow through the SRX without any Layer 3 routing or Layer 2 switching decisions. It effectively bridges two interfaces at Layer 2 while still applying security policies. This ensures that traffic remains unchanged,

  while security policies (such as firewall rules) can still be enforced.

  This is an ideal solution when you need the SRX to act as a "bump in the wire" for security enforcement without changing the traffic or performing complex network lookups.

  Juniper Security Reference:

  Secure Wire Functionality: Provides transparent Layer 2 forwarding with security policy enforcement, making it perfect for scenarios where traffic needs to pass through unchanged. Reference: Juniper Secure Wire Documentation.

• Question 53:

  You have deployed an SRX Series device at your network edge to secure Internet-bound sessions for your local hosts using source NAT. You want to ensure that your users are able to interact with applications on the Internet that require more than one TCP session for the same application session.

  Which two features would satisfy this requirement? (Choose two.)

  A. address persistence

  B. STUN

  C. persistent NAT

  D. double NAT

  Correct Answer: AC

  Address persistence ensures that the same NAT IP address is used for all sessions originating from a single source IP. Persistent NAT maintains connections for applications needing multiple sessions, like VoIP. Additional details are available in Juniper NAT Documentation.

  For applications that require multiple TCP sessions for the same application session (such as VoIP or certain online games), the SRX device needs to handle NAT properly to maintain session continuity. Here's what helps: Address Persistence (Answer A): Address persistence ensures that multiple sessions initiated by the same internal host are mapped to the same external IP address. This is crucial for applications that use multiple TCP sessions to maintain a stateful connection with the external server. Command Example: bash Copy code set security nat source persistent-nat address-persistence Persistent NAT (Answer C): This feature allows the external server to initiate new connections to the internal client using the same NAT translation. It's essential for applications that require consistent NAT mappings across multiple sessions. Command Example: bash Copy code set security nat source persistent-nat permit target-host-port These features ensure that applications with multiple TCP sessions work seamlessly across NAT.

• Question 54:

  Exhibit:

  

  Your company uses SRX Series devices to establish an IPsec VPN that connects Site-1 and the HQ networks. You want VoIP traffic to receive priority over data traffic when it is forwarded across the VPN.

  Which three actions should you perform in this scenario? (Choose three.)

  A. Enable next-hop tunnel binding.

  B. Create a firewall filter that identifies VoIP traffic and associates it with the correct forwarding class.

  C. Configure CoS forwarding classes and scheduling parameters.

  D. Enable the copy-outer-dscp parameter so that DSCP header values are copied to the tunneled packets.

  E. Enable the multi-sa parameter to enable two separate IPsec SAs for the VoIP and data traffic.

  Correct Answer: ABC

  In this scenario, you are prioritizing VoIP traffic over data traffic across an IPsec VPN. Here are the necessary actions:

  Enable next-hop tunnel binding (Answer A): This is required to bind the VPN traffic to a specific tunnel interface (like st0.0). It allows differentiated forwarding behavior (like prioritizing VoIP) for specific traffic types. Command Example: bash Copy code set interfaces st0.0 next-hop-tunnel-service Create a firewall filter (Answer B): The filter will match VoIP traffic based on criteria such as DSCP marking or ports (like port 5060 for SIP). Once identified, the traffic will be associated with a forwarding class, ensuring it gets prioritized. Command Example: bash Copy code set firewall family inet filter VoIP-Filter term VoIP from protocol udp set firewall family inet filter VoIP-Filter term VoIP from port 5060 set firewall family inet filter VoIP-Filter term VoIP then forwarding-class voice Configure CoS (Class of Service) forwarding classes (Answer C): CoS parameters define how the SRX handles different types of traffic (scheduling, shaping, etc.). VoIP traffic must be assigned a higher priority than data. Command Example: bash Copy code set class-of-service forwarding-classes voice set class-of-service forwarding-classes data set class-of-service schedulers voice_scheduler transmit-rate percent 50 These configurations ensure that VoIP traffic is identified, classified, and forwarded with priority.

• Question 55:

  Exhibit:

  

  Referring to the exhibit, which two statements are true? (Choose two.)

  A. Hosts in the Local zone can be enabled for control plane access to the SRX.

  B. An IRB interface is required to enable communication between the Trust and the Untrust zones.

  C. You can configure security policies for traffic flows between hosts in the Local zone.

  D. Hosts in the Local zone can communicate with hosts in the Trust zone with a security policy.

  Correct Answer: BD

  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), an IRB (Integrated Routing and Bridging) interface is required. The IRB interface acts as a gateway

  between Layer 2 and Layer 3 domains.

  Command Example:

  bash

  Copy code

  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

  Copy code

  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.

• Question 56:

  Referring to the exhibit.

  

  You are troubleshooting a new IPsec VPN that is configured between your corporate office and the RemoteSite1 SRX Series device. The VPN is not currently establishing. The RemoteSite1 device is being assigned an IP address on its gateway interface using DHCP.

  Which action will solve this problem?

  A. On the RemoteSite1 device, change the IKE gateway external interface to st0.0.

  B. On both devices, change the IKE version to use version 2 only.

  C. On both devices, change the IKE policy proposal set to basic.

  D. On both devices, change the IKE policy mode to aggressive.

  Correct Answer: D

  Aggressive mode is required when an IP address is dynamically assigned, such as through DHCP, as it allows for faster establishment with less identity verification. More details are available in Juniper IKE and IPsec Configuration Guide.

  The configuration shown in the exhibit highlights that the RemoteSite1 SRX Series device is using DHCP to obtain an IP address for its external interface (ge-0/0/2). This introduces a challenge in IPsec VPN configurations when the public IP

  address of the remote site is not static, as is the case here.

  Aggressive modein IKE (Internet Key Exchange) is designed for situations where one or both peers have dynamically assigned IP addresses. In this scenario, aggressive mode allows the devices to exchange identifying information, such as

  hostnames, rather than relying on static IP addresses, which is necessary when the remote peer (RemoteSite1) has a dynamic IP from DHCP. Correct Action (D): Changing the IKE policy mode to aggressive will resolve the issue by allowing

  the two devices to establish the VPN even though one of them is using DHCP. In aggressive mode, the initiator can present its identity (hostname) during the initial handshake, enabling the VPN to be established successfully.

  Incorrect Options:

  Option A: Changing the external interface to st0.0 is incorrect because the st0 interface is used for the tunnel interface, not for the IKE negotiation.

  Option B: Changing to IKE version 2 would not resolve the dynamic IP issue directly, and IKEv1 works in this scenario.

  Option C: Changing the IKE proposal set to basic doesn't address the dynamic IP challenge in this scenario.

  Juniper References:

  Juniper IKE and VPN Documentation: Provides details on when to use aggressive mode, especially when a dynamic IP address is involved.

• Question 57:

  Referring to the exhibit.

  

  Which IKE mode will be configured on the HQ-Gateway and Subsidiary-Gateway?

  A. Main mode on both the gateways

  B. Aggressive mode on both the gateways

  C. Main mode on the HQ-Gateway and aggressive mode on the Subsidiary-Gateway

  D. Aggressive mode on the HQ-Gateway and main mode on the Subsidiary-Gateway

  Correct Answer: C

  Referring to the exhibit, we can see that the HQ-Gateway has a static IP address (203.0.113.5), while the Subsidiary-Gateway has a dynamic IP address (203.0.113.10). This difference in IP addressing is crucial in determining the correct IKE

  mode configuration.

  Main Mode for Static IP (HQ-Gateway): Main mode is typically used when both VPN peers have static IP addresses. Main mode provides more security because it completes the IKE negotiation in six messages, hiding the identity of the

  participants until the key exchange occurs. Since the HQ-Gateway has a static IP address, main mode is appropriate here.

  Aggressive Mode for Dynamic IP (Subsidiary-Gateway): Aggressive mode is used when one or both VPN peers have dynamic IP addresses. In this mode, the initiator (Subsidiary-Gateway in this case) can present its identity in the first

  message, which is necessary because the dynamic IP may not be known ahead of time. This allows the negotiation to complete more quickly with fewer messages. Hence, aggressive mode is the correct choice for the Subsidiary-Gateway.

  Main mode on the HQ-Gateway and aggressive mode on the Subsidiary- Gateway, because the Subsidiary-Gateway has a dynamic IP, while the HQ-Gateway has a static IP.

  Juniper References:

  Juniper IKE Documentation: Provides details on when to use main mode versus aggressivemode in IPsec VPN configurations based on the static or dynamic nature of IP addresses.

• Question 58:

  You are asked to select a product offered by Juniper Networks that can collect and assimilate data from all probes and determine the optimal links for different applications to maximize the full potential of AppQoE.

  Which product provides this capability?

  A. Security Director

  B. Network Director

  C. Mist

  D. Security Director Insights

  Correct Answer: D

  Juniper Networks' Security Director Insights is the product that provides advanced visibility and analytics by collecting and assimilating data from various probes and sources. Security DirectorInsights is an extension of Security Director but

  focuses on delivering actionable insights into application quality of experience (AppQoE) and security posture. It can process large amounts of data from probes to optimize traffic routing for applications. Security Director Insightsanalyzes

  traffic patterns and makes recommendations for optimal path selection to improve application performance. It integrates with other components like AppQoE to ensure that the best links are selected for each application, improving both

  performance and security.

  Juniper References:

  Juniper Security Director Insights: Details the role of Security Director Insights in optimizing AppQoE by leveraging traffic analysis and probe data.

• Question 59:

  You have deployed two SRX Series devices in an active/passive multinode HA scenario.

  In this scenario, which two statements are correct? (Choose two.)

  A. Services redundancy group 1 (SRG1) is used for services that do not have a control plane state.

  B. Services redundancy group 0 (SRG0) is used for services that have a control plane state.

  C. Services redundancy group 0 (SRG0) is used for services that do not have a control plane state.

  D. Services redundancy group 1 (SRG1) is used for services that have a control plane state.

  Correct Answer: BC

  In a Juniper SRX high-availability (HA) scenario, redundancy is achieved through the use of redundancy groups. Redundancy groups are assigned to control specific functions in an active/passive setup. The HA configuration uses

  redundancy groups to manage failover between the two SRX nodes.

  SRG0 (Services Redundancy Group 0):

  Correct: Option B: SRG0 is used for control plane functions like routing engine redundancy. This group manages the Routing Engine (RE) failover and ensures that routing decisions continue seamlessly during failovers. Correct: Option C:

  SRG0 is also responsible for services without control plane states. These services can include lower-level services such as packet forwarding and stateful firewall services. SRG0 handles both critical and basic functions since control plane

  elements are essential for network operations during failover events.

  SRG1 (Services Redundancy Group 1):

  SRG1, contrary to SRG0, is typically used for data plane services and does not manage control plane state. It handles services like security policies, NAT, and VPN functions but does not involve control plane redundancy.

  Juniper References:

  Juniper SRX HA Documentation: The role of redundancy groups in HA, detailing that SRG0 is reserved for the most crucial services, including control plane failover and basic packet forwarding.

• Question 60:

  You want to use a security profile to limit the system resources allocated to user logical systems.

  In this scenario, which two statements are true? (Choose two.)

  A. If nothing is specified for a resource, a default reserved resource is set for a specific logical system.

  B. If you do not specify anything for a resource, no resource is reserved for a specific logical system, but the entire system can compete for resources up to the maximum available.

  C. One security profile can only be applied to one logical system.

  D. One security profile can be applied to multiple logical systems.

  Correct Answer: BD

  When using security profiles to limit system resources in Juniper logical systems:

  No Resource Specification (Answer B): If a resource limit is not specified for a logical system, no specific amount of system resources is reserved for it. Instead, the logical system competes for resources along with others in the system, up to

  the maximum available. This allows flexible resource allocation, where logical systems can scale based on actual demand rather than predefined limits. Multiple Logical Systems per Security Profile (Answer D): A single security profile can be

  applied to multiple logical systems . This allows administrators to define resource limits once in a profile and apply it across several logical systems, simplifying management and ensuring consistency across different environments.

  These principles ensure efficient and flexible use of system resources within a multi-tenant or multi-logical- system environment.