200-901 practice questions 1–10

1. Question 1 · 530 in bank

   Select 2

   Which two concepts describe test-driven development? (Choose two.)

   • AUser acceptance testers develop the test requirements.
   • BIt enables code refactoring.
   • CTests are created when code is ready for release.
   • DImplementation is driven by incremental testing of release candidates.
   • EWrite a test before writing code.

   Show answer

   Answer: BE

   Explanation

   Need two answers here. E. Write a test before writing code. >> This one is obviously correct for test driven development (TDD). B. It enables code refactoring. >> As Leonhrz pointed out, refactoring can be done without TDD so it does not "enable" it - however it does make it much easier to refactor code since your test will prove if your refactor is successful. Elimination: A. User acceptance testers develop the test requirements. >> This is actually Acceptance Test Driven Development (ATDD). C. Tests are created when code is ready for release. >> This is the complete opposite of TDD. D. Implementation is driven by incremental testing of release candidates. >> This almost sounds correct, but it implies the testing is only for release candidates. https://www.tutorialspoint.com/software_testing_dictionary/release_candidate.htm

   Source: Adapted from community discussion — psyborg

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2. Question 2 · 530 in bank

   What is an advantage of a version control system?

   • Afacilitates resolving conflicts when merging code
   • Bensures that unit tests are written
   • Cprevents over-writing code or configuration files
   • Dforces the practice of trunk-based development

   Show answer

   Answer: A

   Explanation

   A is correct. [..] If you have a team of developers working on a project, all writing new code or changing previously written code, losing those files could set you back weeks or months. Version control can protect your code by allowing changes to be checked in (through a process known as a code commit) to a hierarchical tree structure of folders with files in them. You often don’t know what a developer might need to change or has changed, but the version control system does. Each check-in is tagged with who made the change and what the person changed within the code. Instead of using inefficient techniques such as file locking, a version control system handles concurrent check-ins, allowing two programmers to commit code at the same time. [..] Another aspect of a version control system is the ability to branch and merge code built independently. This is very useful if you are writing code on a part of an application that could conflict with another part written by another team. Page 170 CCNA DevNet (DEVASC) - 200-901

   Source: Adapted from community discussion — designated

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3. Question 3 · 530 in bank

   A developer is attempting to retrieve all the messages from a Cisco Webex space. The server responds by sending the first 1,000 messages. The developer must make additional requests to retrieve the rest of the messages. Which API constraint is described in this scenario?

   • Apayload limiting
   • Bthrottling
   • Cpagination
   • Drate limiting

   Show answer

   Answer: C

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4. Question 4 · 530 in bank

   

   Refer to the exhibit. A developer just finished testing a Python script and wants to save the list of packages and versions installed on the current machine. The developer must make sure that it will not cause any issues if tested on another device due to different library versions. Which line of code needs to be placed on the snippet where the code is missing?

   • Apip freeze 2> requirements.txt
   • Bpip freeze > requirements.txt
   • Cpip freeze => requirements.txt
   • Dpip freeze | requirements.txt

   Show answer

   Answer: B

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5. Question 5 · 530 in bank

   A developer pushes an application to production. The application receives a webhook over HTTPS without a secret. The webhook information contains credentials to service in cleartext. When the information is received, it is stored in the database with an SHA-256 hash. Credentials to the database are accessed at runtime through the use of a vault service. While troubleshooting, the developer sets the logging to debug to view the message from the webhook. What is the security issue in this scenario?

   • ADatabase credentials should be accessed by using environment variables defined at runtime.
   • BDuring the transport of webhook messages, the credentials could be unencrypted and leaked.
   • CDuring logging, debugging should be disabled for the webhook message.
   • DHashing the credentials in the database is not secure enough; the credentials should be encrypted.

   Show answer

   Answer: B

   Explanation

   This is tricky. It seems that all aspects of security are valid until debugging happens. When the webhook is sent, even though the creds are in plain text in the data payload, the transmission is encrypted with HTTPS. Then those creds are stored in with a secure hash. Then they're accessed with a vault service. The only insecure part is the debugging. When the debugging happens, you can see the user/pass in the debugging logs. Technically, that makes B correct, as the logging is done after the HTTPS is decrypted, but it also makes C correct. However, the question asks what the issue is, not what the solution is. Answer C is a solution, not the issue, so I'm going with B.

   Source: Adapted from community discussion — nunyabeez

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6. Question 6 · 530 in bank

   

   Refer to the exhibit. A developer cannot reach the web application behind an NGINX load balancer. The developer sends a request to an application FQDN with cURL but gets an HTTP 502 response. Which action solves the problem?

   • AFix errors in the server configuration, which is behind the load balancer.
   • BBring up the load balancer to the active state.
   • CFix errors in the cURL request sent by the client.
   • DChange the default gateway on the load balancer to an active one.

   Show answer

   Answer: A

   Explanation

   The HyperText Transfer Protocol (HTTP) 502 Bad Gateway server error response code indicates that the server, while acting as a gateway or proxy, received an invalid response from the upstream server.

   Source: Adapted from community discussion — concepcionz

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7. Question 7 · 530 in bank

   

   Refer to the exhibit. A network engineer wants use API update information about device interfaces. The network devices are deployed in a Cisco DevNet Sandbox and have running interfaces. Which value is suitable as the headers variable?

   • A{'Content-Type': 'application/yang.data+yaml', 'Accept': 'application/yang.data+yaml'}
   • B{'Content-Type': 'application/yang.data+json', 'Accept': 'application/yang.data+json'}
   • C{'Content-Type': 'application/yang.data+utf8l', 'Accept': 'application/yang.data+utf8'}
   • D{'Content-Type': 'application/restconf.data+txt', 'Accept': 'application/restconf.data+txt'}

   Show answer

   Answer: B

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8. Question 8 · 530 in bank

   Which action do webhooks enable an application to perform?

   • AIncrease the request rate limit.
   • BPopulate the application with restricted data.
   • CReceive real-time data.
   • DImplement a push model.

   Show answer

   Answer: D

   Explanation

   Simplifying the wording: Webhook enables the app to ( push or receive real time) . The clients should receive real time but the app pushes. Thus D.

   Source: Adapted from community discussion — Sam24681

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9. Question 9 · 530 in bank

   

   Refer to the exhibit. A developer can access the TLS REST API on server A, but cannot access the API on server B. The developer can ping server B. When the developer performs a packet capture on the TLS REST API port on server B, the capture shows that the packet arrived and the server responded. What causes the issue?

   • APort 80 is blocked on the outgoing interface of firewall B.
   • BPort 443 is blocked on the outgoing interface of firewall A.
   • CPort 443 is blocked on the incoming interface of firewall B.
   • DPort 80 is blocked on the incoming interface of firewall A.

   Show answer

   Answer: C

   Explanation

   There is no correct answer. Usually firewalls block or allow destination port and usually they are statefull, which means if the packer going out from inbound interface Firewall B, the respond to this packet will automatically allowed back. Lets say it is stateless and doesn`t work that way, in that case the packet coming back to firewall B`s inbound interface from Server B, is source port 443 and destination port is randomly selected by developer comp. Which blocking or opening 443 in Firewall B inbound interface will not change anything. Ping is working and packet is arriving to Server B, and respond get dropped somewhere, in most cases it could be MTU issue specially there is VPN between. There should be another answer with MTU, however MTU is heavy topic for this certification exam.

   Source: Adapted from community discussion — rafailsharifov

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10. Question 10 · 530 in bank

    DRAG DROP -

    

    Refer to the exhibit. Drag and drop the code from the bottom onto the box where the code is missing to complete the function that adds a new global access rule that denies traffic using the Cisco ASA REST API. Not all options are used. Select and Place:

    

    This is an interactive task on the real exam — a drag-and-drop, hotspot or ordering question. There is nothing to select here, so the answer is shown below for reference.

    Show the answer figure

    Answer: See figure below

    Explanation

    The HTTP 201 Created success status response code indicates that the request has succeeded and has led to the creation of a resource...

    Source: Adapted from community discussion — r3mo

    

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200-901 practice, question 1. 530 questions available.