What is the key difference between strict mode and loose mode unicast RPF?

Strict mode checks the destination address, while loose mode checks the source address

Strict mode requires the source address to be reachable via the receiving interface, while loose mode only requires the source address to be present in the routing table

Strict mode discards packets, while loose mode only logs them

Strict mode is used for IPv4, while loose mode is used for IPv6

What is a common cause of unicast RPF failures in a network?

High bandwidth utilization on the interface

Duplicate IP addresses on different interfaces

Incorrect MTU settings on the interface

Asymmetric routing, where packets take different paths to and from a destination

In which scenario would you typically use loose mode RPF instead of strict mode?

When the network has asymmetric routing, where return traffic may take a different path than incoming traffic

When you need to block all traffic from unknown source addresses

When you are using IPv6 and need to support extension headers

When you want to reduce CPU usage on the device

A service provider uses strict-mode RPF on all customer-facing interfaces. A customer with a dual-homed connection sends traffic with a source address that is announced via BGP from both provider edges. Due to BGP path selection, the provider's return traffic to this source uses the other edge router. What is the impact on the customer's inbound traffic?

Traffic is forwarded normally because the source is reachable via BGP

Traffic is dropped because the source is not reachable via the ingress interface

Traffic is forwarded because BGP routes are exempt from RPF checks

Traffic is dropped only if the customer's source prefix is not in the BGP table

Your network has two upstream ISPs connected to your Junos router. Traffic from ISP-A arrives on ge-0/0/0 and traffic from ISP-B arrives on ge-0/0/1. Due to BGP path selection, return traffic for some destinations learned from ISP-A is sent out ge-0/0/1 toward ISP-B. You need to enable RPF to drop packets with spoofed source addresses, but you must not drop legitimate traffic. Which RPF mode should you configure?

Loose mode on ge-0/0/0 and strict mode on ge-0/0/1

Strict mode on ge-0/0/0 and loose mode on ge-0/0/1

Juniper NetworksCertified Associate, Junos

Domain 7Objective 7

Unicast Reverse-Path-Forwarding (RPF) JN0-105 Practice Questions (Page 1)

Part of the Routing Policy and Firewall Filters domain, which makes up ~11% of our current practice bank. Juniper Networks does not publish an official question count, but from its 90-minute exam (~35–60 total, ~4–7 in this domain), expect 1–1 from this objective — we provide 15 practice questions to prepare you well beyond it. (estimate)

15questions here

3free pages

5concepts

Questions 1–5

1foundation · easy
What is the key difference between strict mode and loose mode unicast RPF?
Select an answer first
2foundation · easy
What is a common cause of unicast RPF failures in a network?
Select an answer first
3foundation · easy
In which scenario would you typically use loose mode RPF instead of strict mode?
Select an answer first
4expert · hard
A service provider uses strict-mode RPF on all customer-facing interfaces. A customer with a dual-homed connection sends traffic with a source address that is announced via BGP from both provider edges. Due to BGP path selection, the provider's return traffic to this source uses the other edge router. What is the impact on the customer's inbound traffic?
Select an answer first
5application · medium
Your network has two upstream ISPs connected to your Junos router. Traffic from ISP-A arrives on ge-0/0/0 and traffic from ISP-B arrives on ge-0/0/1. Due to BGP path selection, return traffic for some destinations learned from ISP-A is sent out ge-0/0/1 toward ISP-B. You need to enable RPF to drop packets with spoofed source addresses, but you must not drop legitimate traffic. Which RPF mode should you configure?
Select an answer first

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Unicast Reverse-Path-Forwarding (RPF) JN0-105 Practice Questions (Page 1)

Questions 1–5

What is the key difference between strict mode and loose mode unicast RPF?

What is a common cause of unicast RPF failures in a network?

In which scenario would you typically use loose mode RPF instead of strict mode?

Keep studying — Routing Policy and Firewall Filters