Network Fundamentals

In an SDN architecture, which API is used by the controller to communicate with network devices to install forwarding rules?

A network administrator is configuring DNS for a corporate domain. An MX record is required to specify the mail server responsible for handling email. Which of the following is a correct example of an MX record?

A network engineer is analyzing traffic patterns and wants to identify characteristics of UDP that affect real-time applications such as VoIP and video streaming. Which two characteristics of UDP make it suitable for these applications? (Choose two.)

An application requires reliable, ordered delivery of data with error checking. Which transport protocol should be used, and what is a key characteristic of this protocol?

During a TCP three-way handshake, which sequence of flags is sent from the client to initiate the connection?

An application needs to discover the MAC address of another device on the same local network. Which protocol does it use?

In the OSI model, which layer is responsible for logical addressing and routing of packets between networks?

Which TWO of the following protocols use UDP as the transport layer protocol? (Choose two.)

In the TCP three-way handshake, which sequence of flags is exchanged to establish a connection?

Which transport protocol is connection-oriented and ensures reliable delivery through acknowledgments and retransmissions?

A DevOps engineer is automating network configuration using REST APIs. The engineer needs to choose between NETCONF and OpenFlow as southbound protocols. Which TWO statements are correct?

A developer runs `python -c "import requests; r=requests.get('https://api.example.com/v1/status'); print(r.json())"` on a Linux host. The command returns a JSON payload instantly, but when the same request is sent to `http://api.example.com/v1/status` the client hangs and later times out with no response. Which network-layer behavior best explains why the HTTPS URL succeeds while the HTTP URL fails?

A developer runs a Python script that uses the requests library to call a REST API endpoint. The script receives an HTTP 401 Unauthorized response. The developer confirms the URL is correct and the server is reachable. Which action should the developer take to resolve the issue?

Which TWO of the following are southbound protocols in SDN?

What is the primary function of a switch in a network?

Which DNS record type is used to verify domain ownership for email security (SPF) and is stored as a text string?

A network engineer is deploying a new application that requires low-latency, high-throughput communication between two data centers. The engineer decides to use UDP instead of TCP for the application's transport protocol. Which two characteristics of UDP make it suitable for this scenario? (Choose two.)

A network administrator needs to assign IP addresses to devices on a subnet with a /25 prefix. How many usable host addresses are available?

Which THREE of the following are features of HTTP/2?

An organization is planning to implement HTTPS for their web services. Which three statements accurately describe the HTTPS protocol? (Choose three.)

What is the primary benefit of using HTTP/2 over HTTP/1.1?

A network automation engineer is using the NETCONF protocol to configure a Cisco IOS XE device. The engineer sends an <edit-config> RPC with a candidate datastore, but the configuration does not take effect until a <commit> operation is performed. Which NETCONF capability must be supported by the device to allow this workflow?

Which THREE of the following are true about HTTP/2 compared to HTTP/1.1? (Select three.)

A network engineer is analyzing a packet capture and notices that a host is sending a TCP segment with the SYN flag set and the ACK flag not set. The destination port is 443. Which of the following best describes what the host is attempting to do?

In Software-Defined Networking (SDN), which interface is used for communication between the controller and the network devices (e.g., switches) to forward traffic?

Which TWO of the following are characteristics of UDP compared to TCP? (Select two.)

A developer is using a REST API to retrieve data from a network controller. The API requires the client to include an API key in the HTTP request header for authentication. Which HTTP header is typically used to carry the API key?

A network engineer is designing a subnet that needs to support 30 usable hosts. Which subnet mask should be used?

A network administrator is configuring subnetting for a new branch office that requires 50 usable host addresses per subnet. The available network is 192.168.10.0/24. What subnet mask should be used to meet the requirement with minimal waste?

A network administrator is configuring a switch and needs to segment traffic into multiple broadcast domains while also allowing communication between them. Which device or feature should be used to achieve this?

A network engineer is analyzing a packet capture and observes that a host sends a TCP segment with the SYN flag set, then receives a segment with both SYN and ACK flags set, and finally sends a segment with only the ACK flag set. Which TCP mechanism is being demonstrated?

A network engineer is configuring a switch and needs to assign an IP address to a VLAN interface for management purposes. The engineer wants to ensure that devices on different VLANs can communicate through the switch. Which feature must be enabled on the switch to allow inter-VLAN routing?

At which layer of the OSI model do switches operate when forwarding frames based on MAC addresses?

Which TCP flag is set in the second step of the three-way handshake?

An organization has a web server that needs to be reachable via both 'www.example.com' and 'example.com'. Which DNS record type should be used to make 'example.com' an alias for 'www.example.com'?

A web application uses HTTPS to secure communications between client and server. What does HTTPS add on top of HTTP to provide encryption and authentication?

A DevOps team is deploying a microservices application that requires both reliable data transfer and low-latency real-time communication. Which two protocols should be used for these respective requirements? (Choose two.)

A network engineer is configuring a new Cisco switch and needs to assign an IP address to a VLAN interface so that the switch can be managed remotely over the network. The engineer enters the commands: interface vlan 10, then ip address 192.168.10.2 255.255.255.0, then no shutdown. However, the interface remains down. What is the most likely cause?

Which of the following is a private IPv4 address range as defined by RFC 1918?

Which layer of the OSI model uses MAC addresses to deliver frames within the same network segment?

Which IP address is a valid host address in the 192.168.1.0/24 network?

A developer runs a Python script that calls a REST API on a remote server. The script hangs indefinitely with no response. The developer opens a terminal and runs `curl -v https://api.example.com/status`. The output shows that the TCP three-way handshake completes, but the TLS handshake never starts. Which of the following is the most likely cause?

A network engineer is subnetting the network 192.168.1.0/24 into subnets that each support at least 50 hosts. What subnet mask should be used?

A developer is configuring a new application server and needs to allow HTTP traffic from web clients. Which port should be opened on the firewall to permit standard unencrypted HTTP traffic?

In Software-Defined Networking (SDN), the control plane is separated from the data plane. Which of the following best describes the function of the southbound API?

In the OSI model, which layer is responsible for session management, including establishing, maintaining, and terminating connections between applications?

A network engineer is troubleshooting connectivity issues and wants to verify the path that packets take from a source to a destination IP address. Which OSI layer is primarily responsible for packet forwarding and routing?

An application developer is using a protocol that does not require a connection setup and has minimal header overhead. Which transport protocol is being used?

An HTTP/2 connection uses multiple concurrent streams over a single TCP connection. Which feature of HTTP/2 enables this?

A developer is writing a script that uses a REST API to configure network devices via NETCONF. Which layer of the SDN architecture does NETCONF belong to?

Which OSI layer is responsible for routing packets across different networks?

A developer is writing a script that uses the Cisco SD-WAN vManage REST API to retrieve a list of devices. The script uses the GET method to https://vmanage.example.com/dataservice/device. The API returns a 401 Unauthorized status code. Which of the following should the developer do to resolve the issue?

Which TWO of the following are characteristics of TLS (Transport Layer Security) used in HTTPS? (Choose two.)

Which wireless security standard provides the strongest encryption and is recommended for enterprise networks as of 2023?

An administrator is configuring DNS records for a company's domain. Which three DNS record types are most commonly used to map hostnames to IP addresses or aliases? (Choose three.)

In HTTP/2, which feature allows multiple concurrent requests and responses to be interleaved on a single connection, improving performance?

A network application requires reliable, ordered delivery of data and uses a three-way handshake to establish a connection. Which transport protocol is being used?

A developer is creating a REST API client that needs to authenticate using credentials passed in the HTTP header. Which header should be used?

A developer is writing a script that must resolve a hostname to an IPv4 address before making an HTTP request. The script uses a DNS resolver library and needs to query for the appropriate record type. Which DNS record type should the script query to obtain the IPv4 address?

An application requires reliable, ordered delivery of data. Which transport protocol should be used?

An application requires reliable, ordered delivery of data with flow control and retransmission of lost segments. Which transport layer protocol should the developer choose and what is a key characteristic of this protocol?

A network engineer is analyzing a packet capture of a TCP session establishment between a client and a server. The engineer observes a packet with the SYN flag set and another with both the SYN and ACK flags set. Which flag will be set in the next packet sent by the client to complete the three-way handshake?

A developer runs `curl -I http://api.example.com/health` and receives `HTTP/1.1 301 Moved Permanently` with a `Location: https://api.example.com/health` header. They want to follow the redirect automatically and print the final response body. Which curl option should they add?

A developer is writing a Python script to interact with a REST API. The script must handle HTTP responses correctly. Which two HTTP status code ranges indicate a successful request and a client error, respectively? (Choose two.)

Which TWO of the following are valid private IPv4 address ranges? (Select two.)

A DNS AAAA record is used to resolve a hostname to what type of address?

A developer's application opens a TCP connection to a REST API, sends a request, and receives a response. The developer then wants to reuse the same connection for several subsequent requests to the same host instead of opening a new socket each time. Which HTTP behavior makes this reuse possible?

A developer is writing a script to interact with a REST API. The API documentation states that the base URL is https://api.example.com/v1/ and that the resource for users is /users. The developer needs to retrieve a list of all users. Which HTTP request should the developer send to the correct endpoint?

A developer is building a Python script that must resolve a hostname to an IPv4 address and then connect to a specific TCP port. The script uses `socket.getaddrinfo(host, port, family=socket.AF_INET, type=socket.SOCK_STREAM)`. What does the returned list contain?

Which THREE of the following are benefits of using an SDN (Software-Defined Networking) architecture compared to traditional networking? (Choose three.)

A developer is writing a Python script that uses the requests library to interact with a REST API. The script must handle common HTTP status codes appropriately. Which two actions should the developer take to ensure robust error handling? (Choose two.)

A developer is troubleshooting an HTTP API call that returns a 404 status code. Which of the following is the most likely cause?

A network engineer is troubleshooting a connectivity issue between two subnets. The engineer uses the traceroute command and observes that packets are reaching the destination but with high latency. Which of the following is the most likely cause of the high latency?

At which layer of the OSI model do MAC addresses operate?

A network administrator is configuring a wireless network and wants to minimize interference. In the 2.4 GHz band, which set of channels are non-overlapping?

An engineer is troubleshooting a network issue where a client cannot reach a server. The client uses HTTPS. Which TWO factors are essential for a successful TLS handshake?

Which TWO of the following are benefits of using UDP over TCP for real-time applications?

A network engineer is troubleshooting an issue where a client cannot reach a web server at 203.0.113.10. The engineer runs a traceroute from the client and sees that the path stops at a router with IP 198.51.100.1, which is the last hop before the destination. The engineer suspects that the router is dropping packets due to an ACL. Which command should the engineer use on the router to verify if an ACL is blocking traffic to the web server?

A network engineer is tasked with segmenting a large broadcast domain into smaller ones using VLANs. In the OSI model, at which layer does a VLAN operate?

An application uses UDP. Which characteristic is true about this application's communication?

A network engineer is configuring a wireless network for a new office. To maximize performance and minimize interference, the engineer decides to use the 5 GHz band. Which of the following is a key advantage of 5 GHz over 2.4 GHz?

A developer is designing a system that requires high reliability and ordered data delivery. The developer chooses TCP. Which THREE features are provided by TCP?

A developer is writing a Python script using requests to retrieve a large JSON payload from an API. The server responds with headers including Content-Encoding: gzip, and the response body appears as binary data. The script must automatically decompress the payload to parse it as JSON. Which requests library behavior should the developer rely on?

An engineer is troubleshooting a VoIP call quality issue. The call uses UDP and experiences packet loss. Which characteristic of UDP most likely contributes to the problem?

A network automation engineer is using `ncclient` to configure a Cisco IOS XE device via NETCONF. The engineer wants to retrieve the running configuration using the `<get-config>` operation with a source of `<running/>`. Which XML element must be included in the RPC to specify the data store?

A network automation engineer must ensure that a Python script running on a management workstation can resolve internal service names such as `inventory.corp.local` and `billing.corp.local`. The workstation currently resolves public names correctly but fails on the internal ones. The engineer inspects `/etc/resolv.conf` and sees a single `nameserver 8.8.8.8` entry. Which change most directly resolves the problem?

A developer is building a Python application that must discover the IP address of a service registered in DNS. The application needs to resolve a domain name to an IPv4 address. Which DNS record type should the application query?

A network engineer is analyzing a packet capture and notices that a TCP session between a client and server is experiencing performance issues. The capture shows that the client sends a segment with the Push (PSH) flag set, but the server's acknowledgment does not immediately follow; instead, the server waits and sends a single acknowledgment for multiple segments. Which TCP mechanism is the server using to optimize network efficiency?

A network operations team is deploying a new application that requires guaranteed bandwidth and low latency between two data centers. The team decides to use MPLS Layer 3 VPN. Which component of MPLS is responsible for forwarding packets based on labels rather than traditional IP routing lookups?

Which wireless standard operates in both 2.4 GHz and 5 GHz bands and is commonly known as Wi-Fi 6?

In an SDN architecture, which layer is responsible for making decisions about where traffic should be forwarded?

An engineer is troubleshooting a connectivity issue between two devices on different VLANs. The switch connecting the devices is configured with 802.1Q trunking. At which OSI layer do VLANs operate?

Which DNS record type is used to verify domain ownership for email security (SPF)?

In a wireless network using 802.11ac, which frequency band does the standard primarily operate in to achieve higher throughput?

Which transport layer protocol is used by HTTP and guarantees reliable delivery?

Which DNS record type is used to map a domain name to an IPv6 address?

A developer is writing a Python script to interact with a REST API. The API requires a JSON payload to create a new resource. Which HTTP method should be used?

A developer is building a Python application that must connect to a REST API hosted on a server. The API requires a persistent connection and the ability to send multiple requests without re-establishing a TCP handshake each time. The developer wants to minimize latency. Which HTTP feature should the application leverage?

A network administrator is configuring a new subnet on a Cisco switch. The subnet uses the address 192.168.10.0/24. The administrator needs to assign an IP address to the switch's management interface so it can be reached from a remote management station on the same subnet. Which of the following IP addresses should be assigned to the switch?

A network administrator is configuring a switch and needs to ensure that devices connected to the same VLAN can communicate with each other. The administrator wants to verify that the switch is correctly forwarding frames within the VLAN. Which of the following best describes the switch's primary function in this scenario?

A network engineer configures an HTTP/2 server. Which feature of HTTP/2 reduces overhead by compressing headers using HPACK?

A developer is building a real-time video streaming application that must minimize delay, even if some packets are lost. Which transport protocol is most appropriate, and why?

In the context of SDN, which API is used between the SDN controller and the network devices to configure forwarding behavior?

An engineer sees that a DNS query for 'www.example.com' returns a CNAME record. What does this mean?

A network administrator is configuring a new subnet for a branch office that requires 50 usable host addresses. The corporate network uses the 192.168.10.0/24 block. Which subnet mask should be used to meet the requirement with minimal waste?

A developer is writing a Python script that will call a REST API. The API documentation states that the service listens on TCP port 443 and requires an encrypted channel. The developer wants to confirm from the command line that the remote host is reachable on that specific port before writing any code. Which command best accomplishes this?

Which THREE of the following are characteristics of HTTP/2 compared to HTTP/1.1?

An engineer is troubleshooting a network issue and needs to verify the MAC address of the next-hop router on a directly connected segment. Which layer of the OSI model does the engineer need to examine to find this information?

A developer is troubleshooting an application that uses HTTP/2. The developer notices that multiple requests are being sent concurrently over a single TCP connection, and the responses are being received out of order. Which HTTP/2 feature allows this behavior?

Which DNS record type is used to verify domain ownership for email security protocols like SPF and DKIM?

A developer is designing a microservices architecture where services need to discover each other using DNS. The team wants to map a service name 'payment-service.example.com' to its IPv6 address. Which DNS record type should be used?

A network engineer is analyzing traffic and needs to identify which applications use UDP. Which three applications commonly use UDP as their transport protocol? (Choose three.)

A network automation script on a Cisco IOS XE device needs to retrieve the current running configuration and then compare it against a known-good baseline stored on a Git server. The script must use a protocol that encrypts all data in transit and supports programmatic, structured retrieval of the configuration without screen-scraping. Which approach should the script use?

Which of the following is a non-overlapping channel in the 2.4 GHz Wi-Fi band?

A network administrator configures a switch port to belong to VLAN 10. Which OSI layer is primarily involved in VLAN tagging?

A network engineer is troubleshooting a connectivity issue between two hosts on different subnets. The engineer suspects a problem with the default gateway configuration. Which two statements about default gateways are correct? (Choose two.)

Which HTTP method is idempotent and used to update a resource by sending the full representation?

An engineer is comparing TCP and UDP for a new telemetry service that sends small, frequent datagrams from thousands of IoT sensors to a collector. The design prioritizes low overhead and does not require retransmission of lost readings. Which two characteristics apply to UDP in this scenario? (Choose two.)

A network administrator is configuring a new subnet for a branch office that requires at least 50 usable host addresses. Which subnet mask would meet this requirement while minimizing address waste?

In the context of SDN, which API allows a network controller to communicate with the forwarding plane of network devices?

A network engineer is designing a subnetting scheme for a company that requires 5 subnets from the 192.168.1.0/24 network. What subnet mask should be used, and how many usable hosts per subnet will be available?

A network engineer captures traffic between a client and a server. The client sends a TCP segment with the SYN flag set. The server responds with a segment that has both SYN and ACK flags set. Which field in the server's response acknowledges the client's initial sequence number?

A network engineer is using a REST API to retrieve a list of network devices from a controller. The API requires authentication using a token. Which HTTP header should be used to include the token in the request?

A developer is writing a Python script that must retrieve the current operational state of a Cisco IOS XE device through its RESTCONF API. The device uses YANG models, and the script must read interface statistics without altering the configuration. Which HTTP method should the script use, and what is the correct URL structure?

A developer is using the Python requests library to call a REST API on a Cisco DNA Center controller. The API requires a token for authentication. The developer writes code to obtain the token and then call the network-device endpoint. Which HTTP header must be included in the second request to authenticate using the token?