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Question 221

Which protocol is commonly used to transfer email from a mail server to another mail server?

1. IMAP
2. POP3
3. SMTP
4. LDAP

Correct Answer: 3

Explanation

Simple Mail Transfer Protocol, or SMTP, is commonly used to send and relay email between mail servers. It is also used when mail clients submit outgoing messages to mail servers, often through authenticated submission services. SMTP commonly uses TCP port 25 for server-to-server communication, while port 587 is widely used for message submission. IMAP and POP3 are primarily used for retrieving email, while LDAP provides directory services. SMTP is therefore the protocol most closely associated with transmitting outgoing email.

Question 222

What is the primary purpose of CIDR?

1. To encrypt IP traffic
2. To provide flexible IP address allocation
3. To replace Ethernet
4. To authenticate wireless users

Correct Answer: 2

Explanation

Classless Inter-Domain Routing, or CIDR, allows IP networks to use flexible prefix lengths instead of relying on traditional fixed address classes. This enables organizations to allocate address space more efficiently and supports route summarization. For example, a /27 network can be created when a smaller network is needed instead of assigning an entire /24. CIDR helps reduce wasted addresses and can also reduce routing table size through aggregation. It does not provide encryption, replace Ethernet, or authenticate wireless users.

Question 223

Which device connects different network media types by converting signals between them?

1. Media converter
2. Firewall
3. Access point
4. Load balancer

Correct Answer: 1

Explanation

A media converter connects different physical network media by converting the signaling required between them. A common example is converting copper Ethernet to fiber Ethernet, allowing devices using different physical media to communicate. Media converters generally operate at the physical layer and do not perform routing or security inspection. Firewalls enforce traffic policies, access points provide wireless connectivity, and load balancers distribute application traffic. Media conversion can be useful when extending networks or connecting existing copper infrastructure to fiber links.

Question 224

Which IPv6 prefix is commonly used for link-local addresses?

1. FC00::/7
2. 2000::/3
3. FE80::/10
4. FF00::/8

Correct Answer: 3

Explanation

IPv6 link-local addresses use the FE80::/10 prefix. These addresses are automatically available on IPv6-enabled interfaces and are intended for communication within the local network segment. They are commonly used for neighbor discovery, router discovery, and other local IPv6 functions. FC00::/7 is associated with unique local addresses, 2000::/3 contains global unicast addresses, and FF00::/8 is used for multicast. Link-local addresses are not intended for normal communication across routed networks.

Question 225

Which protocol is designed to provide directory access over IP networks?

1. SMB
2. LDAP
3. RTP
4. NTP

Correct Answer: 2

Explanation

Lightweight Directory Access Protocol, or LDAP, provides a standardized method for accessing and querying directory services over a network. Directory services can store information about users, groups, computers, and other organizational resources. LDAP can support authentication and authorization workflows when integrated with an appropriate directory system. SMB is commonly used for file and printer sharing, RTP carries real-time media, and NTP synchronizes clocks. LDAP is therefore the protocol most directly associated with accessing centralized directory information.

Question 226

What does a switch do when it receives a frame with an unknown destination MAC address?

1. Drops it immediately
2. Routes it to another subnet
3. Floods it within the appropriate VLAN
4. Sends it to the DNS server

Correct Answer: 3

Explanation

When a switch receives an Ethernet frame whose destination MAC address is not present in its MAC address table, it normally floods the frame out other ports within the same VLAN, excluding the port where the frame arrived. This allows the intended destination to receive the frame and respond, enabling the switch to learn its location. The switch does not normally route the frame to another subnet or send it to DNS. Broadcasts are also flooded within the relevant Layer 2 broadcast domain.

Question 227

Which technology can connect branch offices using centrally managed internet-based WAN links?

1. SD-WAN
2. STP
3. Bluetooth
4. VLAN

Correct Answer: 1

Explanation

Software-Defined Wide Area Networking, or SD-WAN, uses centralized software-based management to control WAN connectivity across multiple sites. It can use different underlying transports, such as broadband internet, cellular connections, MPLS, or other WAN services, depending on the design. SD-WAN can apply policies to select paths based on application requirements, performance, or availability. STP manages Layer 2 loops, Bluetooth provides short-range wireless connectivity, and VLANs provide local segmentation. SD-WAN is therefore designed for flexible, centrally managed WAN environments.

Question 228

Which security mechanism can restrict a switch port to specific MAC addresses?

1. DHCP snooping
2. Port security
3. DNS filtering
4. NAT

Correct Answer: 2

Explanation

Switch port security can restrict which MAC addresses are permitted to use a particular switch port. An administrator can configure allowed addresses manually or use learned addresses depending on the implementation. If an unauthorized MAC address appears, the switch can take an action such as dropping traffic, generating an alert, or disabling the port. DHCP snooping protects against unauthorized DHCP behavior, DNS filtering controls name-resolution requests, and NAT translates addresses. Port security is therefore specifically associated with controlling device access at switch ports.

Question 229

Which network service resolves a hostname such as server.example.com to an IP address?

1. DNS
2. DHCP
3. SNMP
4. NTP

Correct Answer: 1

Explanation

The Domain Name System, or DNS, resolves human-readable hostnames into IP addresses so applications can locate network resources. A DNS server can return IPv4 addresses through A records and IPv6 addresses through AAAA records. DNS also supports other functions, including mail-server identification, aliases, and reverse lookups. DHCP provides network configuration, SNMP supports monitoring, and NTP synchronizes system clocks. DNS is therefore an essential service for applications that use hostnames rather than directly specifying numerical IP addresses.

Question 230

Which wireless standard operates primarily in the 5 GHz band and introduced higher throughput than 802.11n?

1. 802.11b
2. 802.11g
3. 802.11ac
4. 802.11a

Correct Answer: 3

Explanation

IEEE 802.11ac, commonly associated with Wi-Fi 5, operates primarily in the 5 GHz band and introduced significant performance improvements over 802.11n. It supports wider channels, higher modulation rates, and technologies such as multi-user MIMO in later implementations. 802.11b and 802.11g are older standards associated primarily with 2.4 GHz operation, while 802.11a also uses 5 GHz but predates 802.11ac. Understanding wireless generations helps technicians identify compatibility and performance characteristics.

Question 231

Which command displays active network connections and listening ports on many operating systems?

1. netstat
2. ping
3. nslookup
4. tracert

Correct Answer: 1

Explanation

The netstat command can display active network connections, listening ports, routing information, and network statistics depending on the operating system and options used. It is useful when troubleshooting unexpected connections, verifying whether a service is listening on a particular port, or identifying active sessions. Ping tests reachability, nslookup performs DNS queries, and tracert identifies network paths. Administrators can use netstat as part of a broader troubleshooting process to determine which applications and services are communicating across the network.

Question 232

Which routing table entry is typically used when no more specific route matches a destination?

1. Host route
2. Default route
3. Connected route
4. Loopback route

Correct Answer: 2

Explanation

A default route is used when a destination does not match any more specific entry in a routing table. It acts as a catch-all path and commonly directs traffic toward an upstream router or internet gateway. In IPv4, the default route is represented as 0.0.0.0/0, while IPv6 uses ::/0. Connected routes identify directly attached networks, host routes describe individual destinations, and loopback routes refer to local interfaces. Default routes are especially important for internet-bound traffic.

Question 233

Which physical device provides temporary electrical power when the main supply fails?

1. UPS
2. Patch panel
3. Transceiver
4. Router

Correct Answer: 1

Explanation

An Uninterruptible Power Supply, or UPS, provides temporary backup power when the primary electrical supply fails or becomes unstable. A UPS can help network equipment remain operational long enough for power to return or for an orderly shutdown to occur. It can also provide protection against certain power disturbances, depending on the model. Patch panels organize cables, transceivers convert signaling between interfaces or media, and routers forward network traffic. UPS systems are important components of physical infrastructure and network availability planning.

Question 234

Which wireless technology allows multiple antennas to improve throughput and reliability?

1. NAT
2. MIMO
3. STP
4. CIDR

Correct Answer: 2

Explanation

Multiple Input Multiple Output, or MIMO, uses multiple transmit and receive antennas to improve wireless performance. By using multiple spatial streams, MIMO can increase throughput and improve reliability under suitable conditions. Modern Wi-Fi standards use advanced forms of MIMO, including MU-MIMO, which can serve multiple clients more efficiently. NAT translates network addresses, STP prevents Layer 2 loops, and CIDR provides flexible IP addressing and routing prefixes. MIMO is therefore a key wireless technology for improving capacity and performance.

Question 235

Which protocol is commonly used to send diagnostic error messages between IP hosts and routers?

1. ICMP
2. SMTP
3. SMB
4. FTP

Correct Answer: 1

Explanation

Internet Control Message Protocol, or ICMP, is used by network devices and hosts to exchange control and diagnostic information. Utilities such as ping rely on ICMP echo request and echo reply messages to test reachability. ICMP can also report conditions such as unreachable destinations or expired TTL values. SMTP handles email, SMB supports file sharing, and FTP transfers files. ICMP is therefore an important protocol for troubleshooting IP connectivity and communicating certain network-layer errors.

Question 236

Which cloud networking concept provides an isolated virtual network within a cloud environment?

1. VPC
2. NAT
3. STP
4. TFTP

Correct Answer: 1

Explanation

A Virtual Private Cloud, or VPC, provides an isolated logical network environment within a public cloud platform. Organizations can typically define address ranges, subnets, routing, security controls, gateways, and other networking components inside the virtual environment. Although the underlying physical infrastructure is shared by the provider, the VPC provides logical separation between customer environments. NAT can provide address translation, STP manages Layer 2 loops, and TFTP transfers files. VPCs are fundamental building blocks for cloud network architecture.

Question 237

Which protocol is used by DHCP clients during the initial address-assignment process?

1. DHCP
2. DNS
3. LDAP
4. SNMP

Correct Answer: 1

Explanation

DHCP clients use the Dynamic Host Configuration Protocol to obtain network configuration automatically. The initial exchange is commonly remembered using the DORA sequence: Discover, Offer, Request, and Acknowledgment. A client begins by broadcasting a DHCP Discover message because it may not yet know the location of a DHCP server. The server responds with an offer, the client requests an address, and the server acknowledges the lease. This process enables automatic network configuration without manual address assignment.

Question 238

Which type of fiber is generally preferred for very long-distance communications?

1. Multimode fiber
2. Single-mode fiber
3. Coaxial cable
4. UTP

Correct Answer: 2

Explanation

Single-mode fiber is generally preferred for long-distance communication because it has a small core that supports a single propagation mode, reducing modal dispersion and allowing signals to travel much farther. It is commonly used by telecommunications providers, data centers, and organizations requiring long fiber links. Multimode fiber is typically used for shorter distances within buildings and data centers. Coaxial and UTP are copper-based media and are generally more limited in distance compared with fiber-optic technologies.

Question 239

Which network attack attempts to intercept communication between two parties?

1. On-path attack
2. DHCP starvation
3. MAC flooding
4. DNS caching

Correct Answer: 1

Explanation

An on-path attack occurs when an attacker positions themselves between two communicating parties and attempts to observe, modify, or relay their traffic. The attacker may exploit weaknesses in network configuration, authentication, wireless security, or other communication mechanisms. Encryption, certificate validation, secure protocols, and strong authentication can help reduce the risk. DHCP starvation attempts to exhaust address leases, MAC flooding targets switch tables, and DNS caching itself is a normal networking function. An on-path attack specifically involves interception or manipulation of communications.

Question 240

Which metric indicates the amount of data a communication link can theoretically carry per second?

1. Latency
2. Jitter
3. Bandwidth
4. Packet loss

Correct Answer: 3

Explanation

Bandwidth represents the theoretical capacity of a communication link, commonly measured in bits per second. For example, a link rated at 1 Gbps has a theoretical capacity of one billion bits per second under its defined conditions. Actual throughput may be lower because of protocol overhead, congestion, interference, errors, or other factors. Latency measures delay, jitter measures variation in packet timing, and packet loss measures traffic that fails to reach its destination. Bandwidth therefore describes the capacity available for data transmission.