200-901 Network Fundamentals Practice Test 5 — 15 Questions

Question 1

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?

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

Accepted Answer

example.com.  MX  10 mail.example.com.. An MX record specifies the mail server responsible for handling email for a domain, using the format: domain. MX priority mailserver. The priority value (10) indicates preference, with lower values being higher priority. This record directs email delivery to mail.example.com for the example.com domain.

Answer

mail.example.com.  A  192.0.2.1

Answer

example.com.  CNAME  mail.example.com.

Answer

example.com.  TXT  "v=spf1 include:_spf.google.com ~all"

Question 2

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?

Accepted Answer

Layer 2 - Data Link. VLANs operate at Layer 2 (Data Link) of the OSI model because they segment broadcast domains by tagging Ethernet frames with VLAN IDs (802.1Q). This allows logical separation of networks without regard to physical location, and switches use MAC addresses to forward frames within VLANs. Layer 2 is where framing, MAC addressing, and VLAN tagging occur.

Answer

Layer 4 - Transport

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Layer 1 - Physical

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Layer 3 - Network

Question 3

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?

Accepted Answer

UDP. UDP (User Datagram Protocol) is a connectionless transport-layer protocol that does not require a handshake (no SYN/SYN-ACK/ACK) and has minimal header overhead (only 8 bytes, compared to TCP's 20 bytes). This makes it ideal for applications like DNS queries, streaming media, or real-time communications where low latency is more critical than guaranteed delivery.

Answer

TCP

Answer

HTTP

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ICMP

Question 4

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?

Accepted Answer

OpenFlow allows the controller to install flow entries in switches. Option A is correct because OpenFlow is a southbound protocol in SDN in which the controller pushes flow entries (match/action rules) into the flow tables of OpenFlow-enabled switches to dictate forwarding behavior. Option E is correct because NETCONF is a configuration protocol that models device data with YANG and encodes messages in XML over SSH (port 830), making it well suited for automated configuration management. Option B is wrong because NETCONF handles configuration and state retrieval, not real-time per-packet forwarding control, which is OpenFlow's role. Option C is wrong because both NETCONF and OpenFlow are southbound protocols, not northbound APIs. Option D is wrong because OpenFlow is primarily a forwarding-plane control protocol, whereas configuration management is NETCONF's domain.

Answer

NETCONF provides real-time packet forwarding control

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Both protocols are used exclusively for northbound APIs

Answer

OpenFlow is primarily used for configuration management

Question 5

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?

Accepted Answer

Flow control using window size. TCP provides flow control using a sliding window mechanism (Option A), where the receiver advertises a window size in each segment to prevent the sender from overwhelming its buffer. TCP is connection-oriented (Option D): it establishes a session via the three-way handshake (SYN, SYN-ACK, ACK) before data transfer, which underpins its reliability guarantees. TCP also performs sequencing and retransmission (Option E): each byte is numbered with a sequence number, and unacknowledged segments are retransmitted after a timeout or duplicate ACKs, ensuring ordered, loss-free delivery. Option B is incorrect because multicast is not a TCP feature; TCP is strictly unicast, and multicast delivery is handled by UDP-based or specialized protocols. Option C is incorrect because TCP uses a relatively large 20-byte (minimum) header with many fields, whereas UDP has the simple 8-byte header with minimal overhead.

Answer

Multicast support

Answer

Simple header with minimal overhead

Question 6

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

Accepted Answer

Layer 3 (Network). The Network layer (Layer 3) is responsible for logical addressing and routing packets between different networks. Protocols like IP (IPv4/IPv6) use routing tables and algorithms (e.g., OSPF, BGP) to determine the best path for forwarding packets across multiple hops. Without Layer 3, traffic could not leave a local broadcast domain.

Answer

Layer 1 (Physical)

Answer

Layer 4 (Transport)

Answer

Layer 2 (Data Link)

Question 7

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

Accepted Answer

Layer 2 (Data Link). VLAN tagging is defined in IEEE 802.1Q, which operates at Layer 2 (Data Link) of the OSI model. The 802.1Q tag is inserted into the Ethernet frame header, and switches use this tag to make forwarding decisions within the same broadcast domain. Therefore, VLAN tagging is primarily a Layer 2 function.

Answer

Layer 1 (Physical)

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Layer 3 (Network)

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Layer 4 (Transport)

Question 8

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

Accepted Answer

TCP. TCP is the correct choice because it is a connection-oriented transport-layer protocol that guarantees reliable, ordered delivery of data through mechanisms such as sequence numbers, acknowledgments, and retransmissions. UDP does not provide reliability or ordering, HTTP is an application-layer protocol that itself relies on TCP for reliability, and IP is a network-layer protocol that offers best-effort delivery with no guarantees.

Answer

UDP

Answer

HTTP

Answer

IP

Question 9

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

Accepted Answer

SYN and ACK. The TCP three-way handshake begins with the client sending a SYN segment to initiate a connection. In the second step, the server responds with a SYN-ACK segment, which both acknowledges the client's SYN (using the ACK flag) and synchronizes its own sequence number (using the SYN flag). This combined flag is essential for establishing a reliable, bidirectional connection.

Answer

ACK

Answer

SYN

Answer

FIN

Question 10

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?

Accepted Answer

255.255.255.192 (/26). To support at least 50 hosts, you need 6 host bits (2^6 - 2 = 62 usable addresses). A /26 subnet mask (255.255.255.192) provides exactly 6 host bits, meeting the requirement. The original /24 network is borrowed with 2 subnet bits, yielding 4 subnets of 64 addresses each.

Answer

255.255.255.224 (/27)

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255.255.255.240 (/28)

Answer

255.255.255.128 (/25)

Question 11

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

Accepted Answer

TXT record. TXT record is correct because SPF (Sender Policy Framework) is published as a DNS TXT record containing a list of authorized mail servers for a domain. Receiving mail servers query the TXT record to verify that the sending IP is authorized, helping prevent email spoofing. SPF records follow the format v=spf1 followed by mechanisms like ip4, include, and -all.

Answer

A record

Answer

CNAME record

Answer

MX record

Question 12

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

Accepted Answer

It supports multiplexing. HTTP/2 introduces binary framing with a multiplexing layer that allows many concurrent request/response streams to share a single TCP connection. This eliminates HTTP/1.1's head-of-line blocking at the application layer and reduces the need for multiple parallel connections or domain sharding. Multiplexing is the headline feature that delivers HTTP/2's performance gains over HTTP/1.1.

Answer

It is connectionless

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It uses plain text for headers

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It eliminates the need for TLS

Question 13

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

Accepted Answer

Southbound API. The Southbound API is used by an SDN controller to communicate with the forwarding plane (data plane) of network devices, such as switches and routers. It allows the controller to program the forwarding behavior of these devices. Northbound APIs are used for communication with applications, and eastbound/westbound APIs are used for controller-to-controller communication.

Answer

Eastbound API

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Northbound API

Answer

REST API

Question 14

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

Accepted Answer

802.11ax. The IEEE 802.11ax standard, marketed as Wi-Fi 6, is designed to operate in both the 2.4 GHz and 5 GHz frequency bands. It introduces efficiency improvements like OFDMA and MU-MIMO to better handle dense environments. Unlike 802.11ac, which is limited to 5 GHz, 802.11ax supports dual-band operation, making it backward compatible with older devices on both bands.

Answer

802.11n

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802.11ac

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802.11g

Question 15

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

Accepted Answer

The domain is an alias for another domain. A CNAME (Canonical Name) record maps an alias domain name to another canonical domain name. When a DNS query for 'www.example.com' returns a CNAME record, it means 'www.example.com' is an alias for another domain (e.g., 'example.com'), and the resolver must perform a second query to obtain the actual A or AAAA record. This is defined in RFC 1035 and is used to simplify domain management.

Answer

The domain has multiple IP addresses

Answer

The domain uses IPv6

Answer

The IP address is directly provided