Networking Concepts

538 soru

Tüm türler538 Çoktan seçmeli279 Çoklu seçim117 Sayısal19 Eşleştirme95 Sıralama28

A network administrator is creating an Access Control List (ACL) rule on a core router to permit secure, encrypted email retrieval for clients connecting to an internal mail server using IMAPS. Which transport protocol and destination port pair must be explicitly permitted in the ACL configuration?

TCP port 993

UDP port 993

TCP port 143

TCP port 995

Cevabı ve açıklamayı göster

Cevap: TCP port 993

Cevap

TCP port 993 must be permitted in the ACL rule.

IMAPS (Internet Message Access Protocol Secure) uses TCP port 993 by default to establish an encrypted TLS/SSL session for retrieving email messages from a server.

Adım Adım Çözüm

Identify the requested network application protocol and requirement

The scenario specifies IMAPS (Internet Message Access Protocol Secure) for encrypted email retrieval.

Determining the exact service and security level dictates the appropriate protocol standard.

Determine the transport layer protocol required for email retrieval

Email retrieval requires reliable, connection-oriented delivery, which uses TCP rather than UDP.

TCP guarantees ordered delivery and packet acknowledgment necessary for message transfer.

Identify the default port number for IMAPS

Standard unencrypted IMAP uses TCP port 143, while IMAPS (implicit TLS/SSL) uses TCP port 993.

Port 993 is assigned by IANA specifically for IMAPS traffic.

Anahtar Kavram

Common Ports and Protocols (IMAPS over TCP 993)

Tahmini Süre:1m 0s

Soru 362Soru →

A network administrator connects two Layer 2 switches via an 802.1Q trunk port. Switch A is configured with native VLAN $10$ , while Switch B is configured with native VLAN $20$ . If a host assigned to VLAN $10$ sends an untagged frame into Switch A that is forwarded over the trunk, how will Switch B handle the frame upon arrival?

Switch B will accept the untagged frame and forward it to hosts in VLAN 20.

Switch B will automatically drop the frame because devices in different VLANs require a Layer 3 router to exchange data.

Switch B will encapsulate the Layer 2 frame into a Layer 3 IP packet to route it to VLAN 10.

Switch B will change its Spanning Tree Protocol root bridge priority to match VLAN 10.

Cevabı ve açıklamayı göster

Cevap: Switch B will accept the untagged frame and forward it to hosts in VLAN 20.

Cevap

Switch B will accept the untagged frame and process it within VLAN 20, leading to a native VLAN mismatch leak.

Under 802.1Q trunking, traffic associated with the native VLAN is sent across the link untagged. When Switch A transmits a VLAN 10 frame untagged, Switch B accepts the untagged frame and assigns it to its local native VLAN (VLAN 20), resulting in unintended traffic leakage between VLAN 10 and VLAN 20.

Adım Adım Çözüm

Analyze trunk encapsulation behavior for the native VLAN on Switch A

Switch A receives the frame on VLAN 10. Since VLAN 10 is configured as the native VLAN on Switch A's trunk port, Switch A transmits the frame across the trunk without adding an 802.1Q VLAN header tag.

By definition, IEEE 802.1Q does not tag frames associated with the native VLAN.

Analyze frame reception behavior on Switch B

Switch B receives an untagged frame on its trunk port. Switch B assigns all incoming untagged frames to its own configured native VLAN, which is VLAN 20.

Switches map incoming untagged trunk traffic directly to their locally configured native VLAN.

Determine the resulting network behavior

Traffic originating on VLAN 10 is delivered into VLAN 20, creating a security and operational issue known as native VLAN mismatch frame leakage.

Mismatched native VLAN configurations break Layer 2 broadcast domain isolation across trunk links.

Anahtar Kavram

802.1Q Native VLAN Trunking and Mismatch Behavior

Tahmini Süre:1m 15s

Soru 363Soru →

Match each network topology classification to its corresponding operational characteristic or architectural design pattern.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Star Topology matches with central device isolation; Token Ring Topology matches with token-passing sequential transmission; Point-to-Multipoint Topology matches with central base station to subscriber stations; Partial Mesh Topology matches with redundant paths balancing fault tolerance and cost.

Star Topology connects all hosts to a central switch. Token Ring uses deterministic token-passing for access control. Point-to-Multipoint connects one central transmitter to multiple receivers. Partial Mesh provides targeted link redundancy to balance cost and fault tolerance.

Adım Adım Çözüm

Analyze the structural configuration of Star Topology

Identify that Star Topology relies on a central switch/hub connecting all hosts independently.

Centralized star layouts isolate point-to-point physical cable segments.

Evaluate media access methods for Token Ring Topology

Match Token Ring to deterministic token-passing sequence around a logical loop.

Token Ring avoids packet collisions by passing an electronic token sequentially.

Examine Point-to-Multipoint communication patterns

Match Point-to-Multipoint to central base station wireless transmission to multiple subscribers.

P2MP designs establish one central node distributing to multiple endpoints.

Differentiate Partial Mesh from other redundant topologies

Match Partial Mesh to selective redundant links balancing availability and cabling budget.

Partial mesh interconnects essential routers/switches without linking every node pair.

Anahtar Kavram

Classification and operational characteristics of physical and logical network topologies.

Soru 364Soru →

A network technician is verifying the IP configuration of a workstation with the IPv4 address $192.168.1.68/27$ . What is the broadcast address for the subnet to which this workstation belongs?

192.168.1.95

192.168.1.94

192.168.1.63

192.168.1.127

Cevabı ve açıklamayı göster

Cevap: $192.168.1.95$

Cevap

The broadcast address for the subnet is

192.168.1.95

A /27 CIDR prefix corresponds to a subnet mask of 255.255.255.224, creating subnets in block sizes of 32 in the fourth octet. For host address 192.168.1.68, the network ID is 192.168.1.64 and the next network ID is 192.168.1.96. The broadcast address is the final IP before the next network boundary, which is 192.168.1.95.

Adım Adım Çözüm

Determine the block size from the CIDR prefix.

A /27 prefix corresponds to subnet mask 255.255.255.224, giving a block size of

256 - 224 = 32

addresses in the fourth octet.

Calculating the block size identifies the step increment between network boundaries.

Identify the network ID for the host address 192.168.1.68.

Subnet boundaries increment by 32 (0, 32, 64, 96...). The host IP 192.168.1.68 falls into the

192.168.1.64

subnet block.

Finding the network ID establishes the lower boundary of the subnet.

Calculate the broadcast address.

The broadcast address is one less than the next network address (

192.168.1.96 - 1 = 192.168.1.95

The broadcast address is always the final address in a subnet block.

Anahtar Kavram

IPv4 Subnet Boundaries and Broadcast Address Calculation

Tahmini Süre:1m 0s

Soru 365Soru →

A network administrator upgrades an enterprise core network link between two OSPF-enabled routers from $1\text{ Gbps}$ to $10\text{ Gbps}$ . However, after the upgrade, the routers continue to load-balance traffic equally between the new $10\text{ Gbps}$ primary link and a parallel $1\text{ Gbps}$ backup link. Upon inspecting the OSPF database, both interfaces are assigned an OSPF cost metric of $1$ . Which of the following best explains why OSPF calculates an identical path metric for both the $1\text{ Gbps}$ and $10\text{ Gbps}$ links?

The OSPF default reference bandwidth is

100\text{ Mbps}

, which calculates a cost fractional value below

1

for both links and rounds up to a minimum interface cost of

1

OSPF uses Administrative Distance rather than interface bandwidth to determine path metrics, assigning a fixed metric of

1

to all internal link-state routes.

The split horizon mechanism prevents OSPF routers from advertising metric costs lower than

1

across interfaces operating within the same backbone area.

An autonegotiation failure forced a duplex mismatch on the

10\text{ Gbps}

interface, causing OSPF to fall back to a default legacy cost of

1

Cevabı ve açıklamayı göster

Cevap: The OSPF default reference bandwidth is $100\text{ Mbps}$ , which calculates a cost fractional value below $1$ for both links and rounds up to a minimum interface cost of $1$ .

Cevap

The OSPF default reference bandwidth is 100 Mbps, which calculates a cost fractional value below 1 for both links and rounds up to a minimum interface cost of 1.

OSPF calculates path cost using the formula Cost = Reference Bandwidth / Interface Bandwidth. Because the default reference bandwidth in standard OSPF deployments is 100 Mbps, any interface speed equal to or greater than 100 Mbps (such as 1 Gbps or 10 Gbps) calculates to a value less than or equal to 1. Since OSPF costs must be positive integers, both 1 Gbps and 10 Gbps links receive a cost of 1, treating them as equal-cost paths until the auto-cost reference-bandwidth command is configured.

Adım Adım Çözüm

Identify the OSPF metric calculation formula

\text{OSPF Cost} = \frac{\text{Reference Bandwidth}}{\text{Interface Bandwidth}}

OSPF determines interface metrics based on relative link speed.

Calculate the default cost for a

1\text{ Gbps}

link

\frac{100\text{ Mbps}}{1000\text{ Mbps}} = 0.1 \rightarrow \text{rounded up to } 1

The default reference bandwidth in OSPF is

100\text{ Mbps}

, and minimum OSPF metric cost is

1

Calculate the default cost for a

10\text{ Gbps}

link

\frac{100\text{ Mbps}}{10000\text{ Mbps}} = 0.01 \rightarrow \text{rounded up to } 1

Since OSPF metrics must be positive integers, any calculation yielding less than 1 defaults to 1.

Determine the operational outcome

Both paths evaluate to cost

1

, triggering Equal-Cost Multi-Path (ECMP) routing.

To differentiate speeds greater than

100\text{ Mbps}

, the network engineer must manually adjust the `auto-cost reference-bandwidth` setting.

Anahtar Kavram

OSPF Reference Bandwidth and Cost Calculation

Soru 366Soru →

Match each enterprise network administrative service or protocol on the left with its corresponding default port number and primary transport layer protocol on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The correct matches are: TACACS+ corresponds to TCP Port 49; BGP corresponds to TCP Port 179; TFTP corresponds to UDP Port 69; and SIP corresponds to UDP Port 5060.

Each service maps to its precise default port and transport protocol: TACACS+ uses TCP port 49 for administrative access control; BGP uses TCP port 179 for inter-domain routing session maintenance; TFTP uses UDP port 69 for basic configuration transfers; and SIP uses UDP port 5060 for VoIP session management.

Adım Adım Çözüm

Identify the primary transport layer protocol and default port assigned to TACACS+.

TACACS+ requires reliable transmission over TCP port 49 for network device management.

TACACS+ handles full-payload encryption and requires connection-oriented TCP to prevent lost accounting packets.

Determine the transport mechanism and port used by BGP for routing update exchanges.

BGP operates over TCP port 179.

BGP relies on TCP to guarantee ordered, reliable delivery of routing updates between peering routers.

Identify the lightweight file transfer protocol (TFTP) specifications.

TFTP uses UDP port 69.

TFTP omits complex authentication and session state overhead, making UDP port 69 ideal for device firmware loading.

Select the default session initiation protocol (SIP) port for voice/video signaling.

SIP uses UDP port 5060.

SIP uses UDP port 5060 for unencrypted session setup and tear-down of VoIP sessions.

Anahtar Kavram

Standard Service Port and Transport Protocol Mappings

Soru 367Soru →

A network architect is partitioning the IP address space within the block $10.88.24.0/22$ to provision a dedicated subnet for a server farm that requires a minimum of $110$ usable host IP addresses. To maximize IP space efficiency, the architect assigns the smallest standard CIDR prefix that satisfies this host requirement. Assuming the server farm is allocated the first available subnet block starting at $10.88.24.0$ , what is the broadcast address for this specific server subnet?

10.88.24.127

10.88.24.126

10.88.24.128

10.88.24.255

Cevabı ve açıklamayı göster

Cevap: $10.88.24.127$

Cevap

The broadcast address for the allocated server subnet is

10.88.24.127

To accommodate 110 usable hosts, 7 host bits are required (

2^7 - 2 = 126

usable hosts). Subtracting 7 from 32 gives a

/25

prefix (block size of 128 addresses). The first

/25

subnet starting at

10.88.24.0

spans from

10.88.24.0

10.88.24.127

. Thus, the broadcast address is

10.88.24.127

Adım Adım Çözüm

Determine the number of host bits required for 110 usable hosts

7 host bits are needed because

2^7 - 2 = 126 \ge 110

usable addresses (

2^6 - 2 = 62

is insufficient).

Calculating

2^h - 2

accounts for reserving the network ID and broadcast address.

Calculate the CIDR prefix length and block size

The prefix length is

32 - 7 = /25

(

255.255.255.128

). The total block size is

2^7 = 128

IP addresses.

Subtracting host bits from 32 total IPv4 address bits yields the subnet prefix length.

Determine the network range and broadcast address for the first subnet

The subnet range starts at network ID

10.88.24.0

and spans 128 addresses up to

10.88.24.127

. The last IP address in the block (

10.88.24.127

) is the broadcast address.

The broadcast address is always the final address in a subnet block before the next network segment begins.

Anahtar Kavram

Calculating custom CIDR prefixes and broadcast boundaries based on host count requirements

Tahmini Süre:2m 0s

Soru 368Soru →

An enterprise router participating in an OSPF area receives a Link-State Update (LSU) packet containing a revised Link-State Advertisement (LSA) from an adjacent neighbor. Arrange the operational steps in the exact chronological sequence the router executes to process the LSA and update its routing table.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct operational sequence is: 1) Verify the LSU packet header checksum and validate area matching; 2) Compare the sequence number of the received LSA against the existing entry in the LSDB; 3) Store the newer LSA in the local LSDB and flood an LSU copy out all other active OSPF interfaces; 4) Execute Dijkstra's Shortest Path First (SPF) algorithm; 5) Install the newly calculated optimal routes into the router's RIB.

When a router receives an OSPF Link-State Update (LSU), it first validates packet headers and checksums to ensure packet integrity. Next, it compares the LSA sequence number to verify the update is newer than its existing LSDB entry. Once confirmed, it updates its local LSDB and floods the LSA out other OSPF interfaces to maintain area synchronization. After the LSDB is synchronized, the router executes Dijkstra's SPF algorithm on the updated topology map to calculate shortest path trees. Finally, the resulting shortest paths are installed into the Routing Information Base (RIB).

Adım Adım Çözüm

Perform initial packet validation.

The router verifies that the LSU packet is uncorrupted and originated from a valid neighbor within the same area.

Invalid or corrupted control plane packets must be dropped prior to evaluating database changes.

Evaluate LSA freshness using sequence numbers.

The router confirms the received LSA has a higher sequence number than the matching entry in its LSDB.

Sequence numbers prevent stale topological updates from overwriting current network state.

Update local LSDB and flood the LSA.

The LSDB is updated with the new link state, and the update is forwarded to adjacent OSPF routers.

Immediate flooding maintains fast, network-wide link-state convergence.

Run Dijkstra's SPF algorithm.

The router computes a new shortest path tree rooted at itself.

Link-state updates require recalculation of the topological tree to determine optimal paths.

Update the Routing Information Base (RIB).

Best paths calculated by SPF are committed to the routing table.

The routing table uses the best-path output generated by the SPF execution for forward-plane lookup.

Anahtar Kavram

OSPF Link-State Update Processing and SPF Recalculation Sequence

Soru 369Soru →

A network administrator is designing a wireless WAN connection to aggregate traffic from six distant regional utility substations back to a primary operations center. The design requires all substations to transmit telemetry directly to the operations center, but substations do not require direct interconnectivity between each other. Which network topology provides the most cost-effective architecture while meeting these connectivity requirements?

Hub-and-spoke (Point-to-Multipoint)

Full mesh

Physical bus

Storage Area Network (SAN)

Cevabı ve açıklamayı göster

Cevap: Hub-and-spoke (Point-to-Multipoint)

Cevap

Hub-and-spoke (Point-to-Multipoint)

The hub-and-spoke topology (point-to-multipoint) routes all traffic through a central hub node. Because remote substations only need to transmit data back to headquarters and not to one another, hub-and-spoke delivers the exact connectivity required with minimal link overhead and centralized control.

Adım Adım Çözüm

Analyze the traffic and connectivity requirements from the scenario.

The six remote substations must send data to the central operations center, but do not exchange traffic directly with each other.

Determining node communication paths identifies whether direct inter-site links are necessary.

Evaluate candidate network topologies based on cost efficiency and functional fit.

Connecting each remote site exclusively to the central hub satisfies all communication needs while eliminating extra circuit costs.

Hub-and-spoke maximizes cost efficiency by provisioning only

N

links for

N

remote sites, avoiding the

N(N-1)/2

requirement of mesh options.

Anahtar Kavram

Hub-and-Spoke (Point-to-Multipoint) Topology

Tahmini Süre:1m 0s

Soru 370Soru →

A network technician is deploying a new remote office client subnet (VLAN 40). Hosts connected to VLAN 40 are unable to reach the centralized DHCP server located across a Layer 3 WAN link at IP address 10.10.1.50, causing client machines to automatically receive 169.254.x.x addresses. Which of the following configuration actions on the router's VLAN 40 gateway interface will resolve this issue?

Configure an IP helper address specifying the destination IP 10.10.1.50.

Create an AAAA DNS resource record pointing the gateway hostname to 10.10.1.50.

Change the default gateway DHCP relay setting from UDP port 67 to TCP port 67.

Configure the IP helper address to point to the local interface APIPA network address.

Cevabı ve açıklamayı göster

Cevap: Configure an IP helper address specifying the destination IP 10.10.1.50.

Cevap

Configure an IP helper address specifying the destination IP 10.10.1.50.

Because Layer 3 routers block broadcast messages by default, host DHCP DISCOVER broadcasts generated on VLAN 40 cannot reach a DHCP server residing on a different subnet. Setting an IP helper address on the router's local gateway interface acts as a DHCP Relay Agent, converting client broadcasts into directed unicast packets to IP 10.10.1.50.

Adım Adım Çözüm

Identify the cause of client address allocation failure.

Clients on VLAN 40 generate APIPA addresses because local DHCP broadcast frames (DISCOVER) cannot traverse the Layer 3 router boundary to reach the central DHCP server.

Routers drop Layer 2/3 broadcast packets by default.

Determine the required service to enable cross-subnet DHCP functionality.

Deploying a DHCP Relay Agent (IP Helper) on the incoming default gateway interface intercepts broadcast traffic.

The relay agent wraps broadcast DISCOVER messages into unicast IP packets directed to the designated DHCP server address.

Select the correct interface configuration command.

Applying the IP helper address command pointing to 10.10.1.50 enables unicast forwarding of DHCP traffic across the WAN link.

This allows clients to successfully complete the DORA process and acquire valid IP leases from the central scope.

Anahtar Kavram

DHCP Relay / IP Helper Operation across Layer 3 Boundaries

Soru 371Soru →

A workstation user initiates a file download request across a local network. Arrange the encapsulation processing steps executed by the host's networking stack in the correct chronological order, starting from the application request down to physical cable transmission.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order of encapsulation from host data creation to physical transmission is: 1) Application generates raw payload, 2) Transport layer appends port headers (segment), 3) Network layer prepends IP addresses (packet), 4) Data Link layer adds MAC header and FCS trailer (frame), and 5) Physical layer encodes bits into physical signals.

Outbound encapsulation follows a strict top-down progression through the OSI stack. The application layer creates the initial payload data. The transport layer prepends port headers to construct a transport segment. Next, the network layer adds IP addressing headers to construct a network packet. The data link layer then wraps the packet with MAC headers and a Frame Check Sequence (FCS) trailer to build a data link frame. Finally, the physical layer converts the frame's binary bits into physical signals for transmission over the network medium.

Adım Adım Çözüm

Trace the movement of outbound data through the protocol stack

Outbound data traverses top-down from Layer 7 (Application) to Layer 1 (Physical).

Application data must be successively wrapped with control headers at each descending protocol layer before being placed on the wire.

Identify the Protocol Data Unit (PDU) generated at each layer

Data (Layer 7-5) → Segment (Layer 4) → Packet (Layer 3) → Frame (Layer 2) → Bits/Signals (Layer 1).

Each layer treats the upper layer's PDU as raw payload, appending its specific protocol headers and trailers.

Anahtar Kavram

Top-down Data Encapsulation Sequence

Tahmini Süre:1m 30s

Soru 372Soru →

A network administrator is auditing the core network architecture to ensure proper service deployment across enterprise subnets. Match each IP addressing service or feature on the left with its corresponding operational role on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Start of Authority (SOA) record matches the zone administrative metadata description; IP Address Management (IPAM) matches centralized IP tracking and planning; DHCP Option 82 matches appending switch port and VLAN relay metadata; Multicast DNS (mDNS) matches local-link zero-configuration name resolution.

Each feature correctly corresponds to its primary function: the SOA record holds domain zone parameters and contact metadata; IPAM offers central IP address visibility; DHCP Option 82 enriches DHCP discovery packets with relay attachment metadata; and mDNS performs zero-configuration local-link name resolution.

Adım Adım Çözüm

Analyze the DNS Zone Administrative requirement.

Identify that the SOA record specifies authoritative zone data, serial numbers, and refresh timers.

SOA is the fundamental record defining zone parameters for DNS servers.

Identify the service for centralized network IP visibility.

Match IPAM to centralized IP address tracking and integration with DNS/DHCP servers.

IPAM consolidates subnet monitoring and address lifecycle management.

Evaluate the relay security and policy enforcement mechanism.

Match DHCP Option 82 to adding relay agent information (circuit ID/remote ID) to client requests.

Option 82 allows downstream DHCP servers to allocate leases or enforce security based on physical connection details.

Examine serverless name resolution for local links.

Match mDNS to resolving hostnames on local subnets without dedicated DNS infrastructure.

mDNS utilizes multicast packets on port 5353 for zero-configuration host discovery.

Anahtar Kavram

Core functions and operational roles of IP addressing, naming, and management services.

Tahmini Süre:1m 30s

Soru 373Soru →

A network analyst is reviewing security baseline configurations across enterprise infrastructure servers. Match each network protocol on the left with its corresponding default transport protocol, port number, and primary operational function on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

LDAPS pairs with TCP 636 for secure directory services; SFTP pairs with TCP 22 for encrypted file transfers over SSH; SNMP pairs with UDP 161 for device polling; and RDP pairs with TCP 3389 for graphical remote desktop sessions.

Each network protocol correctly corresponds to its standard transport protocol, default port number, and administrative use case: LDAPS uses TCP 636 for secure directory services; SFTP uses TCP 22 for secure SSH file transfers; SNMP uses UDP 161 for device monitoring; and RDP uses TCP 3389 for graphical remote desktop connections.

Adım Adım Çözüm

Determine the transport protocol and port for secure LDAP (LDAPS).

LDAPS uses TCP port 636.

Standard unencrypted LDAP uses TCP port 389, whereas TLS-encrypted LDAPS uses TCP port 636.

Determine the transport protocol and port for SSH File Transfer Protocol (SFTP).

SFTP uses TCP port 22.

SFTP operates as an extension of SSH and relies on the default SSH port TCP 22.

Determine the transport protocol and port for Simple Network Management Protocol (SNMP) polling.

SNMP polling uses UDP port 161.

SNMP request and response messages between NMS managers and network device agents run over connectionless UDP port 161.

Determine the transport protocol and port for Remote Desktop Protocol (RDP).

RDP uses TCP port 3389.

Microsoft RDP utilizes TCP port 3389 to deliver interactive GUI remote administration.

Anahtar Kavram

Standard Network Ports and Transport Layer Protocols

Soru 374Soru →

A network engineer is configuring Variable Length Subnet Masking (VLSM) within the assigned block $10.200.16.0/20$ . The first subnet (Subnet A) must be allocated from the start of the block to support at least $600$ usable host interfaces. The second subnet (Subnet B) must be provisioned immediately following the address space allocated to Subnet A to accommodate at least $250$ usable host interfaces. What is the decimal value of the third octet in the network ID of Subnet B?

Cevabı ve açıklamayı göster

Cevap: 20

Cevap

The decimal value of the third octet in the network ID of Subnet B is 20.

To support at least 600 usable hosts in Subnet A, 10 host bits are required (

2^{10} - 2 = 1022

usable addresses), establishing a /22 subnet mask. With a /22 prefix starting at

10.200.16.0

, the block spans 4 values in the third octet (

16, 17, 18, 19

), covering

10.200.16.0

through

10.200.19.255

. The next available network address for Subnet B starts immediately at

10.200.20.0

. Thus, the third octet decimal value is 20.

Adım Adım Çözüm

Determine the required prefix length for Subnet A.

Subnet A requires a /22 prefix length.

Subnet A needs at least 600 usable host IPs. Since

2^9 - 2 = 510

is insufficient, 10 host bits are required (

2^{10} - 2 = 1022

). The prefix length is

32 - 10 = 22

Calculate the block size and address range for Subnet A.

Subnet A spans

10.200.16.0

10.200.19.255

A /22 prefix has a block size of

2^{(32-22)} = 1024

total addresses (

4

block increments in the third octet). Starting at

10.200.16.0

, the subnet ends at

10.200.19.255

Find the starting network ID for Subnet B.

Subnet B begins at

10.200.20.0

Subnet B must be allocated immediately after the broadcast address of Subnet A (

10.200.19.255

Extract the third octet value.

In the IPv4 address

10.200.20.0

, the third octet is 20.

Anahtar Kavram

Variable Length Subnet Masking (VLSM) block size calculation and sequential subnet allocation.

Soru 375Soru →

A network administrator is configuring workstations on a branch office local area network assigned the IPv4 address block $192.168.50.128/26$ . Which of the following IPv4 addresses are valid, usable host IP addresses within this subnet? (Select TWO.)

Geçerli olan tümünü seçin

192.168.50.130

192.168.50.189

192.168.50.128

192.168.50.191

Cevabı ve açıklamayı göster

Cevap: $192.168.50.130$ ; $192.168.50.189$

Cevap

The addresses

192.168.50.130

and

192.168.50.189

are the valid usable host IP addresses within the

192.168.50.128/26

subnet.

For the assigned block

192.168.50.128/26

, the block size is

64

addresses. The network ID is

192.168.50.128

and the broadcast address is

192.168.50.191

. Usable host addresses range from

192.168.50.129

192.168.50.190

. Both

192.168.50.130

and

192.168.50.189

fall within this valid range.

Adım Adım Çözüm

Calculate the block size and host capacity for the

/26

subnet prefix.

/26

prefix leaves

32 - 26 = 6

host bits. The total number of addresses in the subnet is

2^6 = 64

Determining the address block size establishes subnet boundaries.

Identify the network ID, broadcast address, and usable host address range.

Network ID:

192.168.50.128

. Broadcast Address:

192.168.50.128 + 64 - 1 = 192.168.50.191

. Usable Host Range:

192.168.50.129

through

192.168.50.190

Usable host IP addresses are bounded strictly between the network ID and broadcast address.

Evaluate the given choices against the usable host range.

192.168.50.130

and

192.168.50.189

fall within the

[192.168.50.129, 192.168.50.190]

range.

192.168.50.128

is the network ID and

192.168.50.191

is the broadcast address.

Network IDs and broadcast addresses are reserved and cannot be assigned to hosts.

Anahtar Kavram

IPv4 Subnet Masking and Host Range Determination

Soru 376Soru →

A network analyst is inspecting the de-encapsulation process on a server receiving traffic for a web application. Once the Network Interface Card (NIC) strips the Layer 2 Ethernet frame header and trailer, which layer's header is processed next by the network stack, and what Protocol Data Unit (PDU) is exposed?

The Layer 3 IP header is evaluated next, exposing an IP packet.

The Layer 4 TCP header is evaluated next, exposing a TCP segment.

The Layer 4 UDP header is evaluated next, exposing a UDP datagram.

The Layer 7 HTTP header is evaluated next, exposing application data.

Cevabı ve açıklamayı göster

Cevap: The Layer 3 IP header is evaluated next, exposing an IP packet.

Cevap

The Layer 3 IP header is evaluated next, exposing an IP packet.

During inbound de-encapsulation, protocol headers are stripped in bottom-up order (Layer 2 → Layer 3 → Layer 4 → Layer 7). Once the Layer 2 Ethernet frame header and trailer are removed, the operating system processes the Layer 3 IP header and handles the enclosed IP packet.

Adım Adım Çözüm

Identify the starting point in the de-encapsulation hierarchy

The Layer 2 Data Link frame header and trailer have been removed by the NIC hardware.

Inbound de-encapsulation processes traffic from the bottom of the OSI stack upward.

Determine the next layer in the OSI stack

The payload is delivered to Layer 3 (Network Layer).

Layer 3 directly encapsulates Layer 4 data and sits immediately above Layer 2.

Identify the protocol header and PDU exposed at Layer 3

The IP protocol header is evaluated, exposing the IP packet.

The network stack must inspect IP addressing and routing header fields before handing payload up to Layer 4 transport protocols.

Anahtar Kavram

OSI De-encapsulation Sequence and PDU Layers

Tahmini Süre:1m 0s

Soru 377Soru →

A host workstation on Subnet A transmits data to a server located on Subnet B across an intermediate IP router. Which of the following best describes the header modifications that occur when the router processes and forwards the data unit to the next hop?

The Layer 2 source and destination MAC addresses are updated for the next hop, while the Layer 3 source and destination IP addresses remain unchanged.

The Layer 3 source and destination IP addresses are updated for the next hop, while the Layer 2 source and destination MAC addresses remain unchanged.

Both the Layer 2 MAC addresses and Layer 3 IP addresses are modified at each intermediate routing hop.

The Layer 4 source and destination port numbers are modified for the next hop, while the Layer 2 frame header remains unchanged.

Cevabı ve açıklamayı göster

Cevap: The Layer 2 source and destination MAC addresses are updated for the next hop, while the Layer 3 source and destination IP addresses remain unchanged.

Cevap

The Layer 2 source and destination MAC addresses are updated for the next hop, while the Layer 3 source and destination IP addresses remain unchanged.

During routing, the router de-encapsulates the incoming Layer 2 frame, inspects the Layer 3 IP packet header to determine the outgoing interface and next hop, and then re-encapsulates the IP packet into a new Layer 2 frame. The new frame uses the router egress interface MAC address as the source MAC and the next-hop device MAC address as the destination MAC. The IP header source and destination addresses remain unchanged.

Adım Adım Çözüm

Analyze the role of Layer 2 framing across network boundaries.

Layer 2 headers (MAC addresses) are hop-by-hop parameters that only deliver frames between directly connected interfaces on the same physical link.

When a router receives a frame, it strips the incoming Layer 2 header during de-encapsulation.

Analyze the role of Layer 3 IP headers across network boundaries.

Layer 3 headers (IP addresses) contain the original source host IP and final destination host IP.

IP headers provide end-to-end logical addressing and remain unchanged across intermediate standard routers.

Determine the re-encapsulation process executed by the forwarding router.

The router encapsulates the IP packet into a new Layer 2 frame containing its egress interface MAC address as the source and the target next-hop interface MAC address as the destination.

This enables physical delivery across the next network segment.

Anahtar Kavram

Hop-by-hop Layer 2 re-framing vs. end-to-end Layer 3 packet encapsulation

Tahmini Süre:1m 30s

Soru 378Soru →

A network technician is implementing an automated configuration archiving system for network switches. The system relies on Trivial File Transfer Protocol (TFTP) to push configuration files to a centralized storage server without requiring user authentication or maintaining complex connection sessions. Which of the following port and transport protocol combinations must be permitted on the network firewall to allow this traffic?

UDP port 69

TCP port 21

TCP port 22

UDP port 67

Cevabı ve açıklamayı göster

Cevap: UDP port 69

Cevap

UDP port 69 is required for Trivial File Transfer Protocol (TFTP) traffic.

Trivial File Transfer Protocol (TFTP) is designed as a minimal, lightweight file transfer protocol that operates over User Datagram Protocol (UDP) on well-known port 69. Because it lacks authentication and session overhead, it is commonly used for bootstrapping network devices and backing up router/switch configuration files.

Adım Adım Çözüm

Identify the protocol described in the scenario

The requirement specifies Trivial File Transfer Protocol (TFTP) for lightweight, unauthenticated file pushes.

Determining the exact service protocol dictates the transport layer protocol and default port assignment.

Determine the transport layer protocol and default port for TFTP

TFTP uses UDP on port 69.

TFTP relies on UDP for low-overhead, connectionless transfer rather than TCP.

Match the requirement with the correct firewall port configuration

Permitting UDP port 69 on the firewall allows TFTP configuration traffic to pass.

Firewall rules must match both the specific transport protocol (UDP) and destination port (69).

Anahtar Kavram

Common Network Ports and Protocols (TFTP UDP 69)

Soru 379Soru →

A system administrator is updating firewall access control lists to enable user workstations to securely send outbound messages and retrieve incoming messages from an enterprise mail server over TLS-encrypted sessions. Which TWO of the following port and protocol combinations must be permitted through the firewall to support these secure email services? (Select TWO.)

Geçerli olan tümünü seçin

TCP port 993 for IMAPS

TCP port 587 for SMTP Submission

UDP port 993 for IMAPS

TCP port 110 for POP3S

Cevabı ve açıklamayı göster

Cevap: TCP port 993 for IMAPS; TCP port 587 for SMTP Submission

Cevap

The firewall must permit TCP port 993 for IMAPS and TCP port 587 for SMTP Submission.

Encrypted email retrieval using IMAP over SSL/TLS (IMAPS) standardly uses TCP port 993. Encrypted client email submission using SMTP with TLS standardly uses TCP port 587. Both ports must be open on the firewall to allow secure sending and receiving from mail clients.

Adım Adım Çözüm

Identify the protocol requirements for encrypted email retrieval.

IMAP over TLS/SSL (IMAPS) provides secure mail retrieval on standard TCP port 993.

Unencrypted IMAP uses port 143, whereas encrypted IMAPS defaults to TCP port 993.

Identify the protocol requirements for encrypted outbound email submission.

SMTP Client Submission over TLS operates on TCP port 587.

Legacy unencrypted SMTP uses port 25, while secure client mail submission to an email broker uses TCP port 587.

Evaluate transport layer protocols and port mappings for the incorrect choices.

Rule out UDP-based transport for IMAP and incorrect port assignments for POP3S.

Email retrieval protocols require connection-oriented reliability (TCP), eliminating UDP choices, and POP3S operates on TCP 995 rather than TCP 110.

Anahtar Kavram

Standard Secure Mail Ports (IMAPS TCP 993, SMTP Submission TCP 587, POP3S TCP 995)

Soru 380Soru →

A system administrator monitors outbound network traffic generated by a local workstation initiating a secure shell (SSH) session to a remote server. As the application payload moves down the OSI model protocol stack on the source host, specific encapsulation processes take place. Which of the following statements accurately describe how the data unit is modified during this outbound encapsulation process? (Select TWO)

Geçerli olan tümünü seçin

The Transport layer encapsulates the application data into a segment by prepending a header containing source and destination port numbers.

The Network layer encapsulates the transport segment into a frame by prepending the IP header and appending a Frame Check Sequence (FCS) trailer.

The Network layer encapsulates the transport layer segment into an IP packet by prepending source and destination IP addresses.

The Data Link layer replaces the IP addressing information with port numbers to convert the packet into a physical bitstream.

Cevabı ve açıklamayı göster

Cevap: The Transport layer encapsulates the application data into a segment by prepending a header containing source and destination port numbers.; The Network layer encapsulates the transport layer segment into an IP packet by prepending source and destination IP addresses.

Cevap

The two correct statements are: (1) The Transport layer encapsulates the application data into a segment by prepending a header containing source and destination port numbers, and (2) The Network layer encapsulates the transport layer segment into an IP packet by prepending source and destination IP addresses.

Outbound encapsulation works down the OSI stack: Layer 4 (Transport) prepends port numbers to construct a segment, and Layer 3 (Network) prepends IP addresses to construct a packet. Both of these statements correctly describe PDU encapsulation.

Adım Adım Çözüm

Analyze Layer 4 (Transport Layer) Encapsulation

Application data receives a Layer 4 header (containing source and destination ports like SSH port 22), creating a Segment.

Transport layer encapsulation establishes process-to-process communication.

Analyze Layer 3 (Network Layer) Encapsulation

The Layer 4 Segment is passed down to Layer 3, where an IP header (containing source and destination IP addresses) is prepended, forming a Packet.

Network layer encapsulation provides logical host-to-host addressing across subnets.

Verify Data Link Layer (Layer 2) functions versus higher layer functions

Layer 2 prepends MAC addresses and appends a trailer (FCS) to form a Frame. It does not replace IP addresses or operate with port numbers.

Differentiates Layer 2 frame boundaries from Layer 3 packet and Layer 4 segment boundaries.

Anahtar Kavram

OSI Protocol Data Unit (PDU) Encapsulation Sequence

Tahmini Süre:1m 30s

ÖncekiSayfa 19 / 27Sonraki

Networking Concepts

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram