CCNA 200-301 Practice Quiz – 85 Questions with Answers & Explanations

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📖 All 85 CCNA 200-301 Practice Questions — Full Text & Explanations

Every question from the interactive quiz above, listed here in full with the correct answer and complete explanation, so you can study, search, or bookmark individual questions without needing to restart the quiz.

Question 1: Which OSI layer is responsible for end-to-end communication, error recovery, and flow control?

OSI Model

A. Network Layer (Layer 3)
B. Data Link Layer (Layer 2)
C. Transport Layer (Layer 4) ✓
D. Session Layer (Layer 5)

Explanation: The Transport Layer (Layer 4) handles end-to-end communication, error recovery, and flow control. TCP and UDP both operate here.

Question 2: An administrator pings 10.10.10.1 (the default gateway) and gets 100% packet loss. At which OSI layer is the problem?

OSI Model

A. Data Link Layer
B. Application Layer
C. Access Layer
D. Session Layer
E. Network Layer ✓

Explanation: Ping uses ICMP, a Layer 3 protocol. 100% packet loss to the gateway means the IP address is unreachable — a Network Layer (Layer 3) problem.

Question 3: Which subnet mask is equivalent to /26 in dotted decimal notation?

IP Addressing

A. 255.255.255.0
B. 255.255.255.128
C. 255.255.255.192 ✓
D. 255.255.255.224

Explanation: /26 = 26 ones in binary. Last octet = 11000000 = 192. Mask: 255.255.255.192. Gives 64 addresses, 62 usable hosts.

Question 4: How many usable host addresses are available in a /28 subnet?

IP Addressing

A. 14 ✓
B. 16
C. 30
D. 32

Explanation: /28 = 4 host bits → 2⁴ = 16 addresses. Subtract 2 (network + broadcast) = 14 usable hosts.

Question 5: Review the network topology. Which statements correctly describe the network? (Choose TWO)

Switching

A. There are two broadcast domains in the network. ✓
B. There are four broadcast domains.
C. There are six broadcast domains.
D. There are four collision domains.
E. There are five collision domains. ✓
F. There are seven collision domains.

Explanation: Broadcast domains: The router creates 2 (Sales + Production). Collision domains: Each switch segment + the two router uplinks = 5 collision domains (E).

Question 6: All subnets are in OSPF area 0. Which command issued on R3 shows all LSAs known by R3?

OSPF

A. show running-config
B. show ip ospf interface
C. show ip ospf neighbors
D. show ip route ospf
E. show ip ospf database ✓

Explanation: show ip ospf database displays all LSAs in the router's LSDB. show ip ospf neighbors = adjacency table only. show ip route ospf = installed routes only.

Question 7: A network admin cannot Telnet to the switch from Host B, but pings from Host B to other hosts succeed. What is the issue?

Switching / VLANs

A. Host B and the switch must be in the same subnet.
B. The switch needs a default gateway configured. ✓
C. The switch interface connected to the router is down.
D. Host B needs an IP address in VLAN 1.

Explanation: Host B (VLAN 32) is in a different subnet from the switch's management IP (VLAN 1). The switch needs a default gateway to route replies back to Host B.

Question 8: A technician installed SwitchB and needs to configure it for remote access from the management workstation connected to SwitchA. Which commands are required?

Switch Config

A. SwitchB(config)#interface FastEthernet 0/1 SwitchB(config)#ip address 192.168.8.252 255.255.255.0 SwitchB(config)#no shutdown
B. SwitchB(config)#ip default-gateway 192.168.8.254 SwitchB(config)#interface vlan 1 SwitchB(config)#ip address 192.168.8.252 255.255.255.0 SwitchB(config)#no shutdown ✓
C. SwitchB(config)#interface vlan 1 SwitchB(config)#ip address 192.168.8.252 255.255.255.0 SwitchB(config)#ip default-gateway 192.168.8.254 255.255.255.0 SwitchB(config)#no shutdown
D. SwitchB(config)#ip default-network 192.168.8.254 SwitchB(config)#interface vlan 1 SwitchB(config)#ip address 192.168.8.252 255.255.255.0 SwitchB(config)#no shutdown

Explanation: Option B: A Layer 2 switch needs IP on interface vlan 1 (not a physical port) and a default-gateway for inter-subnet replies.

Question 9: A network administrator cannot establish a Telnet session with the router. What is the cause?

Security / ACL

A. A Level 5 password is not set.
B. An ACL is blocking Telnet access.
C. The vty password is missing. ✓
D. The console password is missing.

Explanation: The vty lines have login but no password is set. Cisco IOS blocks Telnet when login is required but no password exists. ACL 101 blocks SSH (port 22), not Telnet (port 23).

Question 10: What does 'MTU 1500 bytes' mean in the interface output?

Interfaces

A. Max bytes per second on this interface is 1500.
B. Min packet size that can be sent on this interface is 1500 bytes.
C. Max segment size for TCP on this interface is 1500 bytes.
D. Max frame size that can traverse this interface is 1500 bytes. ✓

Explanation: MTU (Maximum Transmission Unit) = the largest frame (Layer 2 PDU) that can traverse the interface. Ethernet default = 1500 bytes. Frames exceeding the MTU are fragmented at Layer 3.

Question 11: Which switch provides the spanning-tree designated port for the segment servicing the printers?

Spanning Tree

A. Switch1
B. Switch2
C. Switch3 ✓
D. Switch4

Explanation: Root Bridge = Switch1 (lowest priority 4096). Switch3 directly connects the printer segment and has the best path to root → Switch3 holds the designated port.

Question 12: Which routing protocol uses Dijkstra's SPF algorithm?

Routing

A. RIP
B. EIGRP
C. OSPF ✓
D. BGP

Explanation: OSPF uses Dijkstra's Shortest Path First to compute best paths from its LSDB. EIGRP uses DUAL. BGP uses path attributes.

Question 13: Which IPv4 address range is reserved for multicast?

IP Addressing

A. 10.0.0.0 – 10.255.255.255
B. 172.16.0.0 – 172.31.255.255
C. 224.0.0.0 – 239.255.255.255 ✓
D. 240.0.0.0 – 255.255.255.254

Explanation: 224.0.0.0 – 239.255.255.255 (Class D) = multicast. OSPF uses 224.0.0.5/6, RIPv2 uses 224.0.0.9, EIGRP uses 224.0.0.10.

Question 14: Which switching method stores the entire frame, checks FCS, then forwards?

Switching

A. Cut-through
B. Fragment-free
C. Store-and-forward ✓
D. Fast-forward

Explanation: Store-and-forward buffers the entire frame, verifies FCS/CRC, then forwards. Highest latency but best error detection.

Question 15: Which IEEE standard defines VLAN trunking / tagging?

VLANs

A. IEEE 802.1Q ✓
B. IEEE 802.3
C. IEEE 802.11
D. IEEE 802.1D

Explanation: 802.1Q inserts a 4-byte VLAN tag into Ethernet frames on trunk links. 802.1D = STP, 802.3 = Ethernet, 802.11 = Wi-Fi.

Question 16: What is the default administrative distance for OSPF?

Routing

A. 90
B. 100
C. 110 ✓
D. 120

Explanation: AD values: Connected=0, Static=1, EIGRP=90, IGRP=100, OSPF=110, IS-IS=115, RIP=120. Lower AD = preferred.

Question 17: Which NAT type creates a permanent one-to-one mapping between a private IP and a public IP?

NAT

A. Dynamic NAT
B. PAT (NAT Overload)
C. Static NAT ✓
D. Policy NAT

Explanation: Static NAT maps one private IP permanently to one public IP. Used for servers that need a consistent public address.

Question 18: Which 802.11 standard operates ONLY at 5 GHz with speeds up to 54 Mbps?

Wireless

A. 802.11b
B. 802.11g
C. 802.11a ✓
D. 802.11n

Explanation: 802.11a = 5 GHz only, 54 Mbps. 802.11b = 2.4 GHz, 11 Mbps. 802.11g = 2.4 GHz, 54 Mbps. 802.11n = dual-band, up to 600 Mbps.

Question 19: Which IPv6 address type is the equivalent of IPv4 private addresses?

IPv6

A. Global Unicast
B. Link-Local
C. Unique Local ✓
D. Multicast

Explanation: Unique Local (FC00::/7) = IPv6 private space. Not routable on the Internet. Link-Local (FE80::/10) = single link only.

Question 20: What is the correct order of DHCP messages between client and server?

DHCP

A. Discover → Offer → Request → Acknowledge ✓
B. Request → Offer → Discover → Acknowledge
C. Discover → Request → Offer → Acknowledge
D. Offer → Discover → Request → Acknowledge

Explanation: DHCP = DORA: Discover → Offer → Request → Acknowledge.

Question 21: Which attack uses a rogue DHCP server to assign itself as the gateway to clients?

Security

A. ARP spoofing
B. DHCP starvation
C. DHCP spoofing ✓
D. MAC flooding

Explanation: DHCP Spoofing: rogue server answers client requests, assigning attacker as gateway (man-in-the-middle). Mitigated by DHCP Snooping.

Question 22: Which command shows the EIGRP neighbor table on a Cisco router?

Routing

A. show ip eigrp topology
B. show ip eigrp neighbors ✓
C. show ip route eigrp
D. show ip eigrp interfaces

Explanation: show ip eigrp neighbors shows neighbor IP, interface, hold time, uptime, and Q/Seq counts.

Question 23: Which statement about standard IPv4 ACLs is true?

ACL

A. Filter on source and destination IP.
B. Should be placed close to the destination.
C. Filter on source IP address only. ✓
D. Can match TCP/UDP port numbers.

Explanation: Standard ACLs (1–99) match source IP only. Extended ACLs filter on src/dst IP and ports.

Question 24: What is the primary purpose of Spanning Tree Protocol (STP)?

Switching

A. Load-balance across multiple links
B. Prevent Layer 2 loops in redundant networks ✓
C. Enable routing between VLANs
D. Encrypt traffic between switches

Explanation: STP (802.1D) prevents Layer 2 loops by blocking redundant ports. Without STP, broadcast storms would crash the network.

Question 25: What is the IPv6 equivalent of ARP?

IPv6

A. DHCPv6
B. ICMPv6 Neighbor Discovery (NDP) ✓
C. OSPF Hello
D. SLAAC

Explanation: NDP uses ICMPv6 Neighbor Solicitation / Advertisement to map IPv6 addresses to MAC addresses (replacing ARP). Uses multicast, not broadcast.

Question 26: What is the maximum hop count supported by RIPv2?

Routing

A. 10
B. 15 ✓
C. 16
D. 255

Explanation: RIPv2 max = 15 hops. A hop count of 16 = unreachable (infinity). Limits RIP to small networks.

Question 27: Which TCP/IP model layer combines the OSI Data Link and Physical layers?

Network Fundamentals

A. Internet
B. Transport
C. Network Access (Link) ✓
D. Application

Explanation: The Network Access (Link) layer of TCP/IP = OSI Layers 1 + 2.

Question 28: Which Cisco switch feature blocks rogue DHCP servers?

Security

A. Port security
B. DHCP snooping ✓
C. Dynamic ARP inspection
D. IP source guard

Explanation: DHCP Snooping marks ports as trusted (server) or untrusted (client). Only trusted ports can send DHCP Offers.

Question 29: Which WAN technology uses PVCs and fixed 53-byte cells?

WAN

A. Frame Relay
B. MPLS
C. ATM ✓
D. PPP

Explanation: ATM uses fixed 53-byte cells (5 header + 48 payload) enabling hardware-speed switching. Frame Relay uses variable-length frames.

Question 30: Which route is used to forward a packet destined for 192.168.1.25?

Routing

A. 192.168.1.0/24 via 10.0.0.1
B. 192.168.1.0/26 via 10.0.0.2
C. 192.168.1.0/28 via 10.0.0.3 ✓
D. 0.0.0.0/0 via 10.0.0.4

Explanation: Longest Prefix Match: 192.168.1.25 fits /24 ✓, /26 (0–63) ✓, /28 (16–31) ✓. /28 is the most specific match → use 10.0.0.3.

Question 31: Which Application-layer protocol translates domain names to IP addresses?

Network Fundamentals

A. DHCP
B. ARP
C. DNS ✓
D. ICMP

Explanation: DNS translates FQDNs to IPs. Uses UDP port 53 (queries) and TCP port 53 (zone transfers).

Question 32: What does 'C' mean in a Cisco router's routing table?

Routing

A. Route learned via OSPF
B. Route learned via static
C. Directly connected network ✓
D. Route learned via CDP

Explanation: Routing table codes: C = Connected, S = Static, O = OSPF, D = EIGRP, R = RIP, B = BGP. Connected = AD 0.

Question 33: What mode must a switch port be in to carry multiple VLANs simultaneously?

VLANs

A. Access mode
B. Trunk mode ✓
C. Dynamic auto
D. Routed port

Explanation: Trunk mode uses 802.1Q tagging to carry multiple VLANs on one link. Access mode carries a single VLAN only.

Question 34: Which encryption standard does WPA2 use?

Security

A. WEP (RC4)
B. TKIP
C. AES-CCMP ✓
D. DES

Explanation: WPA2 uses AES-CCMP. Much stronger than WPA (TKIP) or WEP (RC4). WPA3 uses SAE.

Question 35: Which command configures a default static route on a Cisco router?

Routing

A. ip route 0.0.0.0 0.0.0.0 [next-hop] ✓
B. ip default-route 0.0.0.0 [next-hop]
C. ip route default 0.0.0.0 [next-hop]
D. ip static-route 0.0.0.0 0.0.0.0 [next-hop]

Explanation: ip route 0.0.0.0 0.0.0.0 [next-hop] = the gateway of last resort. Matches any destination not specifically in the table.

Question 36: Which command on R1 creates a static route to the 10.3.3.0/24 network reachable via R2?

Routing

A. ip route 10.3.3.0 255.255.255.0 10.1.1.2 ✓
B. ip route 10.3.3.0 255.255.255.0 10.2.2.2
C. ip route 0.0.0.0 0.0.0.0 10.1.1.2
D. ip route 10.3.3.0 255.255.255.0 Serial0/0

Explanation: From R1, the next hop to reach 10.3.3.0/24 is R2's address on the shared link = 10.1.1.2. Command: ip route 10.3.3.0 255.255.255.0 10.1.1.2

Question 37: What is the purpose of Cisco Discovery Protocol (CDP)?

Switching

A. Dynamically assign IPs to hosts
B. Discover directly connected Cisco devices ✓
C. Prevent Layer 2 loops
D. Encrypt management traffic

Explanation: CDP (Cisco proprietary, Layer 2) discovers neighboring Cisco devices: type, IOS, IP, interfaces. LLDP (802.1AB) is the open-standard equivalent.

Question 38: Which IP address is used to test the local TCP/IP stack?

IP Addressing

A. 0.0.0.0
B. 127.0.0.1 ✓
C. 169.254.0.1
D. 255.255.255.255

Explanation: 127.0.0.1 (loopback) tests the local TCP/IP stack without sending traffic on the network. 169.254.x.x = APIPA link-local.

Question 39: Which OSPF router type connects two different OSPF areas?

OSPF

A. Internal Router
B. Backbone Router
C. Area Border Router (ABR) ✓
D. ASBR

Explanation: An ABR (Area Border Router) connects two or more OSPF areas, maintains separate LSDBs per area, and can summarize inter-area routes.

Question 40: Which VLAN is the default native VLAN on 802.1Q trunks?

VLANs

A. VLAN 0
B. VLAN 1 ✓
C. VLAN 100
D. VLAN 1002

Explanation: VLAN 1 is the default native VLAN — frames on it are sent untagged. Best practice: change native VLAN to an unused VLAN to prevent VLAN hopping.

Question 41: At which OSI layer does a hub operate?

Network Fundamentals

A. Layer 1 – Physical ✓
B. Layer 2 – Data Link
C. Layer 3 – Network
D. Layer 4 – Transport

Explanation: Hubs = Layer 1 (Physical). They repeat electrical signals to all ports. Switches = Layer 2. Routers = Layer 3.

Question 42: Which routing protocol uses bandwidth and delay as its default composite metric?

Routing

A. RIPv2
B. OSPF
C. EIGRP ✓
D. IS-IS

Explanation: EIGRP default metric = bandwidth + delay (K1=1, K3=1, others=0). Formula: 256 × (BW + Delay).

Question 43: Which command enables SSH version 2 on a Cisco IOS router?

Security

A. ip ssh version 2 ✓
B. ssh version 2
C. crypto key generate rsa version 2
D. ip ssh v2 enable

Explanation: ip ssh version 2. Prerequisites: hostname, domain name, RSA keys (2048-bit), VTY lines with transport input ssh.

Question 44: Which STP port state forwards data frames AND learns MAC addresses?

Switching

A. Blocking
B. Listening
C. Learning
D. Forwarding ✓

Explanation: Forwarding: forwards frames + learns MACs. Learning: learns MACs, no forwarding. Blocking/Listening: process BPDUs only.

Question 45: Which IPv6 address is the all-routers multicast address?

IPv6

A. FF02::1
B. FF02::2 ✓
C. FF02::5
D. FF02::A

Explanation: FF02::2 = all routers. FF02::1 = all nodes. FF02::5 = OSPF all routers. FF02::A = EIGRP routers.

Question 46: What does ARP (Address Resolution Protocol) do?

Network Fundamentals

A. Resolve domain names to IP addresses
B. Assign IPs dynamically to hosts
C. Resolve IPv4 addresses to MAC addresses ✓
D. Encrypt traffic between hosts

Explanation: ARP maps Layer 3 IPv4 addresses to Layer 2 MAC addresses via broadcast request and unicast reply.

Question 47: Which QoS mechanism guarantees minimum bandwidth per traffic class?

QoS

A. Traffic policing
B. Traffic shaping
C. CBWFQ ✓
D. Weighted Fair Queuing (WFQ)

Explanation: CBWFQ reserves guaranteed minimum bandwidth per class. Policing = hard drop. Shaping = buffered soft limit. WFQ = fair, no guarantees.

Question 48: Which statement about floating static routes is true?

Routing

A. They use a lower AD than the primary route
B. They use a higher AD than the primary route ✓
C. They are auto-redistributed into dynamic protocols
D. They require OSPF

Explanation: A floating static route has a higher AD than the primary route — dormant while primary is active, kicks in only when primary fails.

Question 49: Which protocol synchronises clocks on network devices?

IP Services

A. SNMP
B. NTP ✓
C. Syslog
D. TACACS+

Explanation: NTP (Network Time Protocol) uses UDP port 123. Critical for log correlation, certificates, and time-based ACLs.

Question 50: Which command shows the MAC address table on a Cisco switch?

Switching

A. show mac address-table ✓
B. show arp
C. show ip interface brief
D. show cam table

Explanation: show mac address-table displays the CAM table: MAC addresses, VLANs, and the ports they were learned on.

Question 51: A company needs 14 subnets each supporting 1000+ hosts from 172.16.0.0/16. Which mask?

IP Addressing

A. /20
B. /21 ✓
C. /22
D. /24

Explanation: /21: 5 subnet bits = 32 subnets ≥14 ✓ | 11 host bits = 2046 hosts ≥1000 ✓. Best fit.

Question 52: Which attack overwhelms a target to make services unavailable?

Security

A. Man-in-the-middle
B. Denial of Service (DoS) ✓
C. Phishing
D. SQL injection

Explanation: A DoS attack floods a target with traffic, preventing legitimate access. DDoS uses multiple sources.

Question 53: What does the 'ip helper-address' command do on a router interface?

Routing

A. Assigns a secondary IP to an interface
B. Forwards DHCP broadcasts to a DHCP server on another subnet ✓
C. Enables OSPF on the interface
D. Configures a backup interface

Explanation: ip helper-address converts client DHCP broadcasts into unicast packets forwarded to the DHCP server — allowing clients on remote subnets to obtain IPs.

Question 54: Which EtherChannel negotiation protocol is Cisco proprietary?

Switching

A. LACP (802.3ad)
B. PAgP ✓
C. RSTP
D. VTP

Explanation: PAgP (Port Aggregation Protocol) = Cisco proprietary. LACP (IEEE 802.3ad) = open standard. Both bundle links for redundancy and bandwidth.

Question 55: Which method lets an IPv6 host auto-configure its address without a DHCPv6 server?

IPv6

A. DHCPv4 relay
B. SLAAC (Stateless Address Autoconfiguration) ✓
C. ARP request
D. Static assignment only

Explanation: SLAAC uses Router Advertisement (RA) messages to give the host a network prefix; the host builds its own address using EUI-64 or random bits.

Question 56: Which correctly describes the difference between TCP and UDP?

Network Fundamentals

A. UDP provides reliable ordered delivery; TCP does not.
B. TCP provides reliable ordered delivery; UDP does not. ✓
C. Both TCP and UDP provide reliable delivery.
D. TCP is Layer 2; UDP is Layer 3.

Explanation: TCP = reliable, ordered, connection-oriented (HTTP, FTP, SSH). UDP = connectionless, best-effort, fast (DNS, DHCP, streaming).

Question 57: Which OSPF router type imports external routes (e.g. from EIGRP or static) into the OSPF domain?

Routing

A. Internal Router
B. Area Border Router (ABR)
C. Backbone Router
D. Autonomous System Boundary Router (ASBR) ✓

Explanation: An ASBR (Autonomous System Boundary Router) redistributes routes from outside OSPF (e.g. EIGRP, static, BGP) into OSPF using the redistribute command. ABRs connect areas; ASBRs connect to external routing domains.

Question 58: What is the maximum data rate of 802.11ac (Wi-Fi 5) Wave 1?

Wireless

A. 54 Mbps
B. 600 Mbps
C. 1.3 Gbps ✓
D. 6.9 Gbps

Explanation: 802.11ac Wave 1 = up to 1.3 Gbps. Wave 2 ≈ 3.5 Gbps. 802.11ax (Wi-Fi 6) = 9.6 Gbps.

Question 59: Which AAA protocol encrypts the ENTIRE authentication packet (not just the password)?

Security

A. RADIUS
B. TACACS+ ✓
C. LDAP
D. Kerberos

Explanation: TACACS+ encrypts the entire packet and separates Authentication/Authorization/Accounting. RADIUS encrypts only the password.

Question 60: What is the primary path selection attribute used by BGP?

Routing

A. Hop count
B. Bandwidth
C. AS_PATH ✓
D. OSPF cost

Explanation: BGP prefers the route with the shortest AS_PATH. Full selection order: Weight → LOCAL_PREF → Locally originated → AS_PATH → ORIGIN → MED…

Question 61: What is the minimum size of an IPv4 header?

Network Fundamentals

A. 8 bytes
B. 20 bytes ✓
C. 32 bytes
D. 40 bytes

Explanation: Minimum IPv4 header = 20 bytes (without options). IPv6 header = fixed 40 bytes.

Question 62: Which VTP mode allows creating, modifying, and deleting VLANs and propagates updates?

VLANs

A. Client
B. Transparent
C. Server ✓
D. Off

Explanation: VTP Server can create/edit/delete VLANs and advertise to Clients. Transparent mode forwards VTP but maintains its own local VLAN database.

Question 63: Which protocol sends log messages from devices to a central server?

IP Services

A. NTP
B. SNMP
C. Syslog ✓
D. NetFlow

Explanation: Syslog (UDP 514) sends log messages to a syslog server. Severity 0 (Emergency) to 7 (Debug).

Question 64: In EIGRP, what is the metric a neighbor reports to reach a destination called?

Routing

A. Feasible Distance (FD)
B. Reported Distance (RD) / Advertised Distance ✓
C. Successor route
D. Feasible Successor

Explanation: RD (Reported Distance) = neighbor's metric to destination. FD = RD + metric to neighbor = total local cost. Lowest FD = Successor route.

Question 65: Which commands enable port security with shutdown violation on a Cisco switch?

Security

A. switchport port-security maximum 1
B. switchport port-security violation shutdown
C. Both A and B, plus 'switchport port-security' to enable ✓
D. ip dhcp snooping limit rate 1

Explanation: Port security needs three commands: switchport port-security (enable), maximum [n] (MAC limit), violation shutdown (err-disable on violation).

Question 66: Which 2.4 GHz channels are non-overlapping (US)?

Wireless

A. Channels 1, 5, 9
B. Channels 1, 6, 11 ✓
C. Channels 1, 7, 13
D. Channels 2, 6, 10

Explanation: Channels 1, 6, 11 are non-overlapping in 2.4 GHz (US). Use these in adjacent APs to avoid co-channel interference.

Question 67: What is the primary benefit of route summarization?

Routing

A. Increases routing table size
B. Reduces table size and routing protocol overhead ✓
C. Converts static routes to dynamic
D. Enables load balancing

Explanation: Route summarization reduces table size, decreases update traffic, speeds convergence, and isolates topology changes.

Question 68: Which WAN encapsulation is commonly used on DSL connections?

Network Fundamentals

A. HDLC
B. Frame Relay
C. PPPoE ✓
D. ATM only

Explanation: PPPoE (PPP over Ethernet) is used on DSL, providing authentication and IP assignment. HDLC is used on leased lines.

Question 69: How many bits are in an IPv6 address?

IPv6

A. 32 bits
B. 64 bits
C. 128 bits ✓
D. 256 bits

Explanation: IPv6 = 128 bits (8 groups of 4 hex digits). IPv4 = 32 bits. IPv6 provides ~3.4 × 10³⁸ addresses.

Question 70: After OSPF converges, what does it periodically send to maintain adjacencies?

Routing

A. LSA packets
B. DBD packets
C. Hello packets ✓
D. LSR packets

Explanation: Hello packets maintain OSPF adjacencies. Default: every 10s on Ethernet. No Hello within 40s = neighbor declared down.

Question 71: Which SNMP version provides authentication AND encryption?

IP Services

A. SNMPv1
B. SNMPv2c
C. SNMPv3 ✓
D. SNMPv2u

Explanation: SNMPv3 supports AuthPriv (authentication + AES/DES encryption). v1 and v2c use cleartext community strings.

Question 72: What is the primary function of VTP (VLAN Trunking Protocol)?

Switching

A. Synchronise VLAN databases across switches in a domain ✓
B. Route traffic between VLANs
C. Encrypt VLAN traffic on trunks
D. Prevent VLAN hopping attacks

Explanation: VTP (Cisco proprietary) syncs VLAN configs across a domain. VTP Server → VTP Client propagation.

Question 73: Which best describes a half-duplex connection?

Network Fundamentals

A. Data flows in both directions simultaneously
B. Data can only be sent, not received
C. Data flows in one direction at a time ✓
D. Data is encrypted in both directions

Explanation: Half-duplex: one direction at a time. Hubs force half-duplex. Full-duplex: simultaneous both ways, no collisions.

Question 74: Which command verifies OSPF neighbor adjacencies on a Cisco router?

Routing

A. show ip ospf database
B. show ip ospf neighbor ✓
C. show ip route ospf
D. debug ip ospf events

Explanation: show ip ospf neighbor shows neighbor ID, state (FULL = adjacency), Dead timer, address, and interface.

Question 75: Which cloud model provides virtualized servers, storage, and networking over the Internet?

Cloud & Automation

A. SaaS – Software as a Service
B. PaaS – Platform as a Service
C. IaaS – Infrastructure as a Service ✓
D. NaaS – Network as a Service

Explanation: IaaS = VMs, storage, networking on demand (AWS EC2, Azure VMs). PaaS = dev platforms (Heroku). SaaS = complete apps (Office 365, Gmail).

Question 76: Refer to the exhibit. R1's routing table shows the routes below. Which type of route does R1 use to reach host 10.10.13.10/32?

Routing Table

A. default route
B. network route ✓
C. host route
D. floating static route

Explanation: 10.10.13.10 is a host address (/32). The routing table has 10.10.13.0/25 via OSPF which covers the range .0–.127, matching 10.10.13.10. This is a network route (a route to a subnet, not a single host). A host route would appear as /32. A default route is 0.0.0.0/0. No floating static is present.

Question 77: Refer to the exhibit. Router1's routing table is shown. Which prefix does Router1 use to forward traffic to Host A (10.10.13.214)?

Longest Prefix Match

A. 10.10.10.0/28
B. 10.10.13.0/25
C. 10.10.13.144/28
D. 10.10.13.208/29 ✓

Explanation: Host A = 10.10.13.214. Apply longest-prefix match: /25 covers .128–.255 ✓ | /28 (10.10.13.144) covers .144–.159 ✗ | /29 (10.10.13.208) covers .208–.215 ✓ — this is longer. 10.10.13.208/29 is the most specific match and wins.

Question 78: Refer to the exhibit. R2 has no specific route to 8.8.8.8. Which route does it use and via which next-hop?

Default Route

A. OSPF route via 192.168.10.0
B. Directly connected via Gi0/0
C. Default static route via 10.1.1.1 ✓
D. No route — packet is dropped

Explanation: 8.8.8.8 matches no specific entry. The gateway of last resort (S* 0.0.0.0/0) is used — a default static route via 10.1.1.1. This is the catch-all for any destination not matched by a more specific prefix.

Question 79: Refer to the exhibit. Router R1 receives a packet destined for 172.16.4.200. Which route does R1 select?

Longest Prefix Match

A. 172.16.0.0/16 via 10.0.12.1
B. 172.16.4.0/24 via 10.0.12.1
C. 172.16.4.0/26 via 10.0.13.1
D. 172.16.4.192/26 via 10.0.12.1 ✓

Explanation: 172.16.4.200 — check each prefix: /16 ✓, /24 (.0–.255) ✓, /26 (.0–.63) ✗, /26 (.192–.255) ✓. The longest match is 172.16.4.192/26 (prefix length 26 beats /24 and /16). Router selects via 10.0.12.1.

Question 80: Refer to the exhibit. All links run OSPF. R1 needs to reach 10.2.2.0/24 on R3. Which path does OSPF select based on cost (bandwidth)?

OSPF

A. Via R4 — lower hop count
B. Via R2 — lower OSPF cost (20) ✓
C. Via R4 — higher bandwidth
D. Load-balance across both paths

Explanation: OSPF selects the path with the lowest cumulative cost. R1→R2→R3 = cost 10+10 = 20. R1→R4→R3 = cost 100+100 = 200. OSPF installs the path via R2 (cost 20). OSPF does not use hop count — that's RIP.

Question 81: Refer to the exhibit. R1 learns about 192.168.10.0/24 via both OSPF and EIGRP. Which route does it install in the routing table?

Administrative Distance

A. OSPF route — lower metric (20)
B. EIGRP route — lower AD (90) ✓
C. Both are installed — equal-cost load balancing
D. Static route overrides both

Explanation: When the same prefix is learned by multiple protocols, the router installs the one with the lowest Administrative Distance (AD). EIGRP AD = 90 beats OSPF AD = 110. Metric is only compared between routes from the same protocol.

Question 82: Refer to the exhibit. A packet arrives at R1 destined for 10.5.5.100/32. Out of which interface does R1 forward the packet?

Routing Table

A. GigabitEthernet0/0
B. GigabitEthernet0/1 ✓
C. GigabitEthernet0/2
D. Dropped — no specific route

Explanation: 10.5.5.100 — check both /25 subnets: 10.5.5.0/25 covers .0–.127 → .100 fits ✓. 10.5.5.128/25 covers .128–.255 → .100 does not fit ✗. Longest prefix match selects 10.5.5.0/25 via GigabitEthernet0/1.

Question 83: Refer to the exhibit. R1 has a primary OSPF route and a floating static route to 10.99.0.0/24. The OSPF neighbor goes down. Which route does R1 now use?

Floating Static Route

A. Default route via 0.0.0.0/0
B. Packet is dropped — no route
C. Floating static route via ISP (AD 200) ✓
D. EIGRP redistributed route

Explanation: A floating static route has a deliberately high AD (200 here) so it stays hidden while the OSPF route (AD 110) is active. When OSPF fails and the route is removed, the floating static becomes active — providing automatic failover via the ISP link.

Question 84: Refer to the exhibit. R1's routing table has a static route with a next-hop of 10.0.0.2. What must also be present for R1 to successfully forward packets?

Routing Table

A. A host route /32 for 10.0.0.2
B. A route to reach next-hop 10.0.0.2 (e.g. directly connected 10.0.0.0/30) ✓
C. A default route 0.0.0.0/0
D. An ARP entry for 192.168.50.1

Explanation: Static routes with a next-hop IP require a recursive lookup: the router must also have a route to reach 10.0.0.2 itself (e.g. the directly connected 10.0.0.0/30). Without it, the next-hop is unresolvable and the static route is inactive — shown as an asterisk or missing from the route table.

Question 85: Refer to the exhibit. R1 receives a packet for 10.10.13.150. Given the routing table, which route and exit interface does R1 use?

Longest Prefix Match

A. 10.10.13.0/25 via Gi0/0
B. 10.10.13.128/26 via Gi0/0
C. 10.10.13.128/28 via Gi0/1 ✓
D. 10.10.13.144/28 via Gi0/1

Explanation: 10.10.13.150 — test each: /25 (.0–.127) ✗ | /26 (.128–.191) ✓ | /28-a (.128–.143) ✗ | /28-b (.144–.159) ✗. Candidates are /26 and /28-a is out of range. 10.10.13.128/28 covers .128–.143 — .150 doesn't fit. So /26 (.128–.191) wins as longest match. Route: 10.10.13.128/26 via Gi0/0... Wait — re-check: /26=64 hosts, .128+64=.192, so .128–.191 ✓ .150 fits. /28=16 hosts: .128–.143 ✗. Winner: 10.10.13.128/26 via Gi0/0.

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