200-901 Practice Test 39 — 15 Questions

Question 1

A DevOps team manages a hybrid cloud environment with on-premises Cisco Nexus switches and AWS VPCs using Terraform. They have a configuration management tool that pushes VLAN and interface configurations to the Nexus switches. Recently, they noticed that after a Terraform run that updates the AWS VPC subnets, some on-premises switches lose connectivity to the cloud. The team suspects a mismatch between the VLAN configurations on the Nexus switches and the AWS VPC subnets. They have a centralized source of truth stored in a Git repository containing YAML files for network definitions. Which action should the team take first to resolve the issue and prevent future occurrences?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Compare the Git repository's YAML definitions with the actual switch configurations and AWS VPC subnets, then correct any discrepancies.. The team's centralized source of truth in Git (YAML files) should be the authoritative reference for network definitions. By comparing these definitions against both the actual Nexus switch configurations and AWS VPC subnets, the team can identify and correct any drift or mismatch. This aligns with Infrastructure as Code (IaC) best practices, ensuring that all environments are synchronized from a single, version-controlled source before making any changes.

Answer

Restore the Nexus switch configurations from the most recent backup.

Answer

Modify the Terraform scripts to automatically update Nexus switches when AWS VPC subnets change.

Answer

Manually reconfigure the VLANs on the Nexus switches to match the AWS VPC subnets.

Question 2

A network automation engineer is writing a Python script to interact with the Cisco Meraki Dashboard API. The script currently makes GET requests to retrieve a list of networks and then makes subsequent requests for each network to get device details. However, the script is slow due to network latency. The engineer wants to improve performance without changing the API's functionality. Which approach best addresses the performance issue?

Accepted Answer

Use parallel requests with asyncio for concurrent API calls.. Using asyncio with an async HTTP library (like aiohttp) allows the script to send multiple GET requests concurrently rather than sequentially, reducing the total wall-clock time dominated by network latency. This approach improves performance without altering the API's functionality or the data being retrieved.

Answer

Wrap all API calls in a single transaction.

Answer

Increase the timeout value in each request.

Answer

Use a POST request instead of GET to combine both operations.

Question 3

A network administrator notices that a host with IP 192.168.1.10/25 cannot communicate with a host at 192.168.1.200/25. What is the most likely reason?

Accepted Answer

The subnet mask is incorrect; they are on different subnets.. With a /25 mask (255.255.255.128), the network is divided into two subnets: 192.168.1.0-127 and 192.168.1.128-255. The two hosts are in different subnets and require a router to communicate.

Answer

The default gateway is missing.

Answer

The ARP cache is corrupted.

Answer

The hosts are using different DNS servers.

Question 4

A developer is writing a Dockerfile for a Node.js application. Which TWO instructions are commonly used to define the command that runs when the container starts?

Accepted Answer

CMD. The CMD instruction in a Dockerfile provides default arguments for the container's entrypoint or defines the command to execute when the container starts. For a Node.js application, CMD is commonly used to specify the startup command, such as `CMD ["node", "app.js"]`, which runs the Node.js process. This instruction can be overridden at runtime by providing a command after `docker run`.

Answer

RUN

Answer

START

Answer

EXPOSE

Question 5

A developer is using Git for version control of a Python library. A colleague accidentally committed a large sensitive file. Which Git command sequence should be used to remove the file from history without losing subsequent changes?

Accepted Answer

git filter-branch or git filter-repo. `git filter-branch` and `git filter-repo` are designed to rewrite Git history, allowing you to permanently remove a large sensitive file from all commits. This is necessary when a file has been committed and pushed, as simple removal with `git rm` only affects the latest commit and leaves the file accessible in prior history. Using these commands ensures the file is purged from the entire repository history without losing subsequent changes, as they replay the commit graph while filtering out the specified file.

Answer

git rm --cached && git commit

Answer

git rebase -i && git commit --amend

Answer

git revert HEAD

Question 6

A developer is making a GET request to a REST API and needs to specify that the response should be in JSON format. Which HTTP header should be set?

Accepted Answer

Accept. The Accept header is used by the client to tell the server which media types (e.g., application/json) it can understand and prefers for the response. In a GET request, the client does not send a body, so Content-Type is irrelevant for specifying the response format. Setting Accept: application/json ensures the server returns JSON if it supports that format.

Answer

Content-Type

Answer

User-Agent

Answer

Authorization

Question 7

When designing a REST API client for a Cisco DNA Center deployment, which authentication method should be used to obtain a token for subsequent API calls?

Accepted Answer

HTTP Basic authentication to obtain a token.. Cisco DNA Center uses HTTP Basic authentication to obtain a token. The client sends a POST request to the /dna/system/api/v1/auth/token endpoint with a Base64-encoded string of the username and password in the Authorization header. The server returns a token that must be included in subsequent API calls via the X-Auth-Token header.

Answer

OAuth 2.0 client credentials grant.

Answer

API key in the request header.

Answer

Client certificate in the request.

Question 8

A developer is using Cisco DNA Center API to add a new device to the inventory. Which HTTP method should be used for this operation?

Accepted Answer

POST. The POST HTTP method is used to create a new resource on the server. When adding a new device to the Cisco DNA Center inventory, you are creating a new device entry, which aligns with the POST method as defined by RESTful API conventions. Cisco DNA Center's device onboarding API endpoint (e.g., /dna/intent/api/v1/network-device) specifically requires a POST request to add a device.

Answer

PATCH

Answer

GET

Answer

DELETE

Question 9

Which three configuration management tools can be used with Cisco devices for automation? (Choose three.)

Accepted Answer

Puppet. Puppet is a configuration management tool that uses a declarative language to define system state. It can manage Cisco devices via the cisco_ios module, which uses SSH or NX-API to apply configurations, making it suitable for network automation.

Answer

Nagios

Answer

SaltStack

Question 10

Which TWO HTTP methods are considered safe (idempotent and without side effects on the server)?

Accepted Answer

HEAD. (HEAD) is correct because the HEAD method is defined as idempotent and safe per RFC 7231: it retrieves the same headers as a GET request but without a response body, causing no side effects on the server. Option E (GET) is also correct because GET is explicitly defined as a safe method that only retrieves data and does not modify server state, making it idempotent.

Answer

POST

Answer

PUT

Answer

DELETE

Question 11

An engineer is using EEM on an IOS XE device. They want to trigger an applet when a specific syslog message appears. Which event trigger type should they use?

Accepted Answer

event syslog pattern. EEM supports syslog pattern matching as an event trigger.

Answer

event interface

Answer

event cli match

Answer

event timer

Question 12

Based on the exhibit, what is the frequency of the telemetry subscription?

Accepted Answer

Every 500 milliseconds. The exhibit shows a telemetry subscription with a 'period' of 500, which in Cisco model-driven telemetry (MDT) is expressed in milliseconds. Therefore, the frequency is every 500 milliseconds, making option B correct.

Answer

Every 500 seconds

Answer

When the management connection is re-established

Answer

On-change only

Question 13

A developer is designing a Python script to parse the output of 'show ip interface brief' from a Cisco IOS device. The output is stored in a string variable. The developer wants to extract only the interfaces that are up/up. The current code uses regular expressions but often fails because the interface names contain special characters (e.g., GigabitEthernet1/0/1). Which approach should the developer use to reliably parse the output?

Accepted Answer

Use a structured data format like JSON or YAML if available from the device. Cisco IOS devices can output structured data formats like JSON or YAML when commands are prefixed with 'pipe' modifiers (e.g., `show ip interface brief | json`). Parsing structured data eliminates the need for fragile regex patterns that fail on interface names containing special characters like slashes or hyphens. This approach is more reliable and maintainable, aligning with modern network automation practices.

Answer

Use the 're' module with a more complex pattern that escapes special characters

Answer

Use split on whitespace and check column values

Answer

Use a CSV parser with a custom delimiter

Question 14

Which TWO are valid methods to secure a REST API? (Choose two.)

Accepted Answer

Use HTTPS to encrypt data in transit.. HTTPS (HTTP over TLS) encrypts the entire HTTP conversation, including headers and payload, using Transport Layer Security (TLS). This prevents eavesdropping, man-in-the-middle attacks, and tampering of data in transit. For a REST API, HTTPS is a fundamental security requirement to protect sensitive data and credentials from being exposed on the network.

Answer

Use HTTP with basic authentication.

Answer

Embed API keys in the URL query string.

Answer

Implement rate limiting to prevent abuse.

Question 15

Which three components are required to set up a Webex webhook for message creation events? (Choose three.)

Accepted Answer

Resource type (e.g., "messages"). A is correct because every Webex webhook must specify a resource type to define which API resource triggers the webhook. For message creation events, the resource type must be "messages" to indicate that the webhook listens for changes to message resources. Without this, the webhook cannot know which data model to monitor.

Answer

Room ID to filter messages

Answer

API access token as a query parameter