Cisco 300-440 Practice Exam Questions & Answers

Cisco SD-WAN IPsec tunnels are different from native IPsec VPN tunnels in several ways. One of the unique features of Cisco SD-WAN IPsec tunnels is that they support real-time dynamic path selection, which means that they can automatically choose the best path for each application based on the network conditions and policies. This feature improves the performance, reliability, and efficiency of the network traffic. Native IPsec VPN tunnels, on the other hand, do not have this capability and rely on static routing or manual configuration to select the path for each tunnel. This can result in suboptimal performance, increased latency, and higher costs.Reference:=Traditional IPsec Versus Cisco SD-WAN IPsec,SD-WAN vs IPsec VPN's - What's the difference?,SD-WAN vs. VPN: How Do They Compare?,Traditional IPSEC Versus SD-WAN IPSEC

To send traffic into an IPsec tunnel to the cloud VPN gateway, the engineer must configure two actions:

Configure access lists that match the interesting user traffic. This is the traffic that needs to be encrypted and sent over the IPsec tunnel. The access lists are applied to the crypto map that defines the IPsec parameters for the tunnel.

Configure policy-based routing (PBR). This is a technique that allows the engineer to override the routing table and forward packets based on a defined policy. PBR can be used to send specific traffic to the IPsec tunnel interface, regardless of the destination IP address. This is useful when the cloud VPN gateway has a dynamic IP address or when multiple cloud VPN gateways are available for load balancing or redundancy.Reference:

Designing and Implementing Cloud Connectivity (ENCC) v1.0, Module 3: Implementing Cloud Connectivity, Lesson 3: Implementing IPsec VPNs to the Cloud, Topic: Configuring IPsec VPNs on Cisco IOS XE Routers

Security for VPNs with IPsec Configuration Guide, Cisco IOS XE, Chapter: Configuring IPsec VPNs, Topic: Configuring Crypto Maps

[Cisco IOS XE Gibraltar 16.12.x Feature Guide], Chapter: Policy-Based Routing, Topic: Policy-Based Routing Overview

The end-to-end ping between the office user PC and the AWS EC2 instance is not working because either the security group rules for the host VPC are blocking the ICMP traffic or the IPsec SA counters are showing errors or drops. To diagnose the loss of connectivity, the engineer should check both the security group rules and the IPsec SA counters. The network security group rules on the host VNET are not relevant because they apply to Azure, not AWS. The IPsec SA configuration on the Cisco VPN router and the AWS private virtual gateway are not likely to be the cause of the problem because the site-to-site VPN tunnel is already up and the site-to-site routing works correctly.Reference:=

Designing and Implementing Cloud Connectivity (ENCC, Track 1 of 5), Module 3: Configuring IPsec VPN from Cisco IOS XE to AWS, Lesson 3: Verify IPsec VPN Connectivity

Security for VPNs with IPsec Configuration Guide, Cisco IOS XE, Chapter: IPsec VPN Overview, Section: IPsec Security Association

AWS Documentation, User Guide for AWS VPN, Section: Security Groups for Your VPC

A highly secure multitier application in AWS that includes S3, RDS, and some additional private links requires specific routing and bucket policies to keep the traffic safe. The reasons are as follows:

Specific routing policies are needed to ensure that the traffic between the tiers is routed through the private links, which provide secure and low-latency connectivity between AWS services and on-premises resources12.The private links can also prevent the exposure of the data and the application logic to the public internet12.

Bucket policies are needed to control the access to the S3 buckets that store the application data34.Bucket policies can specify the conditions under which the requests are allowed or denied, such as the source IP address, the encryption status, the request time, etc.34.Bucket policies can also enforce encryption in transit and at rest for the data in S334.

1: AWS PrivateLink

2: AWS PrivateLink FAQs

3: Using Bucket Policies and User Policies

4: Bucket Policy Examples

To enable the OMP advertisement of BGP routes for a specific VRF instance on a Cisco IOS XE SD-WAN device, the engineer must first configure the global address-family ipv4 and then enable bgp advertisement under the vrf definition.This will allow the device to advertise the BGP routes learned from the cloud provider to the OMP control plane, which will then distribute them to the other SD-WAN devices in the overlay network1

The problem is that the site-list ''All-Site'' has a higher match sequence than the site-list ''Hub'', which means that the policy for ''All-Site'' will take precedence over the policy for ''Hub'' for any site that belongs to both lists. This creates a conflict and prevents the engineer from adding a new centralized control policy in Cisco vManage. To resolve this issue, the site-list ''All-Site'' should be configured with a new match sequence that is lower than the sequence for site-list ''Hub'', so that the policy for ''Hub'' will be applied first and then the policy for ''All-Site'' will be applied only to the remaining sites that are not in the ''Hub'' list.Reference:=

Designing and Implementing Cloud Connectivity (ENCC, Track 1 of 5), Module 3: Cisco SD-WAN Cloud OnRamp for Colocation, Lesson 3: Cisco SD-WAN Cloud OnRamp for Colocation - Centralized Control Policies

Cisco SD-WAN Cloud OnRamp for Colocation Deployment Guide, Chapter 4: Configuring Centralized Control Policies

Cisco SD-WAN Configuration Guide, Release 20.3, Chapter: Centralized Policy Framework, Section: Policy Configuration Overview