Free Juniper JN0-637 Practice Exams - Page 4 of 6

Question #31

Referring to the exhibit,

which two statements are correct about the NAT configuration? (Choose two.)

A . Both the internal and the external host can initiate a session after the initial translation.
B . Only a specific host can initiate a session to the reflexive address after the initial session.
C . Any external host will be able to initiate a session to the reflexive address.
D . The original destination port is used for the source port for the session.

Question #32

You are deploying IPsec VPNs to securely connect several enterprise sites with ospf for dynamic routing. Some of these sites are secured by third-party devices not running Junos.

Which two statements are true for this deployment? (Choose two.)

A . OSPF over IPsec can be used for intersite dynamic routing.
B . Sites with overlapping address spaces can be supported.
C . OSPF over GRE over IPsec is required to enable intersite dynamic routing
D . Sites with overlapping address spaces cannot be supported.

Reveal Solution Hide Solution

Correct Answer: BC
BC

Explanation:

Understanding the Scenario:

Objective: Deploy IPsec VPNs connecting multiple enterprise sites using OSPF for dynamic routing.

Challenge: Some sites use third-party devices not running Junos OS.

Considerations:

Compatibility between Juniper and third-party devices.

Support for dynamic routing protocols (OSPF) over IPsec VPNs.

Handling overlapping IP address spaces.

Option Analysis:

Option A: OSPF over IPsec can be used for intersite dynamic routing.

OSPF Characteristics:

OSPF uses multicast addresses (224.0.0.5 and 224.0.0.6) for neighbor discovery and routing updates.

IPsec Limitations:

Standard IPsec tunnel mode does not support multicast traffic natively. Multicast traffic cannot traverse IPsec tunnels unless encapsulated. Juniper Solution:

Juniper devices can use routed VPNs (route-based VPNs) with st0 interfaces, allowing OSPF over IPsec.

However, this requires support from both ends of the VPN tunnel.

Third-Party Devices:

May not support OSPF over IPsec without additional configurations.

Conclusion:

Option A is not universally true in this scenario due to third-party device limitations.

Reference: "OSPF can be run over IPsec VPNs using route-based VPNs, but interoperability with third-party devices must be verified."

Source: Juniper TechLibrary – OSPF over IPsec VPNs

Option B: Sites with overlapping address spaces can be supported.

Overlapping IP Address Spaces:

Occurs when different sites use the same IP subnets.

Can cause routing ambiguities and conflicts.

Solution:

NAT over VPN:

Use Network Address Translation (NAT) to translate overlapping IP addresses to unique addresses.

Juniper devices support NAT over IPsec VPNs.

Third-Party Device Considerations:

Need to ensure third-party devices support NAT over IPsec. Many enterprise-grade devices provide this functionality. Conclusion:

Option B is true; overlapping address spaces can be supported using NAT.

Reference: "When sites have overlapping IP addresses, NAT can be used over IPsec VPNs to resolve address conflicts."

Source: Juniper TechLibrary – NAT with IPsec VPNs

Option C: OSPF over GRE over IPsec is required to enable intersite dynamic routing.

GRE Tunnels:

Generic Routing Encapsulation (GRE) can encapsulate multicast and broadcast traffic.

Allows OSPF packets to be transmitted over IPsec VPNs.

IPsec Encryption:

GRE tunnels can be encrypted using IPsec for secure communication.

Interoperability:

GRE over IPsec is a common method to support OSPF between devices from different vendors. Third-party devices are more likely to support GRE over IPsec than OSPF over IPsec directly. Conclusion:

Option C is true; using OSPF over GRE over IPsec is required in this scenario.

Reference: "To run OSPF between devices that do not support multicast over IPsec, GRE tunnels can be used over IPsec VPNs."

Source: Juniper TechLibrary – Configuring GRE over IPsec

Option D: Sites with overlapping address spaces cannot be supported.

Contradicts Option B.

As established, overlapping address spaces can be supported using NAT over IPsec VPNs.

Conclusion:

Option D is false.

Conclusion:

Correct Answers: B and C

Option B: Overlapping address spaces can be supported using NAT over IPsec VPNs.

Option C: OSPF over GRE over IPsec is required to enable intersite dynamic routing, especially when third-party devices are involved.

Additional Detailed

Why OSPF over IPsec May Not Be Feasible (Option A):

Multicast Traffic:

OSPF relies on multicast for neighbor discovery and updates. IPsec in tunnel mode does not natively support multicast traffic. Third-Party Devices:

May not support proprietary extensions or configurations required to run OSPF directly over IPsec.

Workaround:

Encapsulate OSPF multicast packets within GRE tunnels, which can carry multicast traffic over unicast IPsec tunnels.

Why OSPF over GRE over IPsec Is Necessary (Option C):

GRE Tunnels:

Encapsulate multicast/broadcast traffic into unicast packets. Allow routing protocols like OSPF to function over IPsec VPNs. Compatibility:

GRE is a widely supported protocol across different vendors. Facilitates interoperability between Juniper and third-party devices. Supporting Overlapping Address Spaces (Option B):

NAT over IPsec:

Translates private IP addresses to unique addresses across the VPN.

Prevents routing conflicts and allows communication between sites with overlapping subnets.

Considerations:

Requires proper configuration on both ends of the VPN tunnel.

Third-party devices must support NAT over IPsec.

Reference to Juniper Security Concepts:

Route-Based VPNs:

"Route-based VPNs use virtual tunnel interfaces (st0) and support dynamic routing protocols over

IPsec."

Source: Juniper TechLibrary – Route-Based VPNs

GRE over IPsec:

"GRE over IPsec allows the transmission of multicast and non-IP protocols over IPsec tunnels." Source: Juniper TechLibrary – GRE over IPsec Overview NAT with IPsec VPNs:

"NAT can be applied to IPsec VPN traffic to resolve overlapping address issues and facilitate communication between sites."

Source: Juniper TechLibrary – NAT with IPsec

Final Notes:

Interoperability:

When working with third-party devices, always verify compatibility for protocols and features.

Best Practices:

Use GRE over IPsec for dynamic routing protocols requiring multicast support across IPsec VPNs.

Implement NAT over VPN when dealing with overlapping address spaces.

Question #33

You Implement persistent NAT to allow any device on the external side of the firewall to initiate traffic.

Referring to the exhibit, which statement is correct?

A . The target-host parameter should be used instead of the any-remote-host parameter.
B . The port-overloading parameter needs to be turned off in the NAT source interface configuration
C . The target-host-port parameter should be used instead of the any-remote-host parameter
D . The any-remote-host parameter does not support interface-based NAT and needs an IP pod to work.

Reveal Solution Hide Solution

Question #34

You are configuring an interconnect logical system that is configured as a VPLS switch to allow two logical systems to communicate.

Which two parameters are required when configuring the logical tunnel interfaces? (Choose two.)

A . Encapsulation ethernet must be used.
B . The virtual tunnel interfaces should only be configured with two logical unit pairs per logical system interconnect.
C . The logical tunnel interfaces should be configured with two logical unit pairs per logical system interconnect.
D . Encapsulation ethernet-vpls must be used.

Reveal Solution Hide Solution

Question #35

You are asked to create multiple virtual routers using a single SRX Series device. You must ensure that each virtual router maintains a unique copy of the routing protocol daemon (RPD) process.

Which solution will accomplish this task?

A . Secure wire
B . Tenant system
C . Transparent mode
D . Logical system

Reveal Solution Hide Solution

Question #36

Which two statements are correct about the ICL in an active/active mode multinode HA environment? (Choose two.)

A . The ICL is strictly a Layer 2 interface.
B . The ICL uses a separate routing instance to communicate with remote multinode HA peers.
C . The ICL traffic can be encrypted.
D . The ICL is the local device management interface in a multinode HA environment.

Reveal Solution Hide Solution

Question #37

You are asked to establish a hub-and-spoke IPsec VPN using an SRX Series device as the hub. All of the spoke devices are third-party devices.

Which statement is correct in this scenario?

A . You must ensure that you are using aggressive mode when incorporating third-party devices as your spokes.
B . You must statically configure the next-hop tunnel binding table entries for each of the third-party spoke devices.
C . You must create a policy-based VPN on the hub device when peering with third-party devices.
D . You must always peer using loopback addresses when using non-Junos devices as your spokes.

Reveal Solution Hide Solution

Question #37

You are asked to establish a hub-and-spoke IPsec VPN using an SRX Series device as the hub. All of the spoke devices are third-party devices.

Which statement is correct in this scenario?

A . You must ensure that you are using aggressive mode when incorporating third-party devices as your spokes.
B . You must statically configure the next-hop tunnel binding table entries for each of the third-party spoke devices.
C . You must create a policy-based VPN on the hub device when peering with third-party devices.
D . You must always peer using loopback addresses when using non-Junos devices as your spokes.

Reveal Solution Hide Solution

Question #39

You have deployed a new site as shown in the exhibit. Hosts in the 10.10.10.0/24 network must access the DB1 server. The DB1 server must also have internet access the DB1 server encrypted.

Which two configuration statements will be required as part of the configuration on SRX1 to satisfy this requirement? (Choose two)

A . set security macsec interfaces ge-0/0/1 connectivity association access-sw
B . set protocols 12-learning global mode transpårent-bridge
C . set security forwarding-options secure-wire access-sw interface ge-0/0/1.0
D . set security macsec connectivity-association access-sw security-mode static-cak

Reveal Solution Hide Solution

Question #40

You are attempting to ping the IP address that is assigned to the loopback interface on the SRX series device shown in the exhibit.

What is causing this problem?

A . The loopback interface requires encapsulation.
B . The loopback interface is not assigned to a security zone.
C . The incorrect interface index ID is assigned to the loopback interface.
D . The IP address on the loopback interface is a private address.

Reveal Solution Hide Solution