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Tüm alıştırma soruları

1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 1841Soru →

During a security audit of an enterprise network infrastructure, an engineer reviews several identified security vulnerabilities and proposed mitigation steps across administrative access, ACL filtering, and switchport security. Which of the following correctly pairs an identified security threat or vulnerability with its proper mitigation strategy?

Cevabı ve açıklamayı göster

Cevap: To mitigate eavesdropping and tampering of administrative command authorization, deploy TACACS+ for AAA because TACACS+ encrypts the entire packet payload, unlike RADIUS which encrypts only the password.

Cevap

Deploying TACACS+ for AAA correctly mitigates eavesdropping on administrative authorization because TACACS+ encrypts the complete body of every packet and separates authentication from authorization, whereas RADIUS encrypts only the password field.
Deploying TACACS+ is the correct mitigation for administrative eavesdropping because TACACS+ encrypts the complete body of every packet and separates authentication, authorization, and accounting functions, allowing granular command-level authorization in ciphertext over TCP.

Adım Adım Çözüm

1
Analyze protocol encryption characteristics for administrative access security.
TACACS+ uses TCP port 49 and encrypts the entire payload of every packet. RADIUS uses UDP ports 1812/1813 (or 1645/1646) and encrypts only the password attribute.
Cleartext command authorization payloads in RADIUS expose administrative operations to network sniffing.
2
Evaluate access control list behavior.
Cisco IPv4 ACLs feature an invisible implicit 'deny ip any any' at the end of every list.
Relying on an assumed implicit permit would lead to unexpected blocking of desired traffic or misunderstanding of ACL flow.
3
Evaluate port security persistent MAC address learning.
Sticky MAC learning writes dynamically discovered MAC addresses into the running-config file in RAM.
Failing to save running-config to startup-config causes all sticky MAC bindings to disappear when the switch restarts.

Anahtar Kavram

Key Security Concepts, Threats, Vulnerabilities, and Mitigations
Tahmini Süre:2m 0s
Soru 1842Soru →

Router R1 learns the destination network 10.50.0.0/1610.50.0.0/16 dynamically via internal EIGRP, which has a default Administrative Distance (AD) of 90. A network administrator wants to configure a floating static route pointing to next-hop 192.168.12.2192.168.12.2 to serve as a backup path when the EIGRP route fails. Which two conditions or behaviors apply to this floating static route implementation? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The floating static route must be configured with an Administrative Distance value greater than 90.; The floating static route will be placed into the active routing table only when the primary EIGRP route is removed.

Cevap

To configure a functional floating static route for an EIGRP primary path, the static route must specify an Administrative Distance greater than 90 (the default EIGRP AD). Consequently, the backup route will only be installed into the active routing table when the lower-AD EIGRP route disappears.
A floating static route acts as a backup mechanism by using an Administrative Distance (AD) higher than that of the primary route (in this case, EIGRP AD of 90). Cisco IOS populates the active routing table with the lowest AD available; thus, the static route stays out of the routing table until the primary route fails and is withdrawn.

Adım Adım Çözüm

1
Identify the Administrative Distance (AD) of the primary routing protocol.
Internal EIGRP has a default AD of 90.
Floating static routes rely on AD comparison to remain dormant until the primary route fails.
2
Determine the required Administrative Distance for the backup floating static route.
The static route's AD must be set higher than 90 (e.g., 95 or 130).
If configured with a lower AD (such as 80 or 1), the static route would override the EIGRP path during normal operation.
3
Analyze how Cisco IOS handles routing table selection for multiple sources.
Only the path with the lowest AD is placed in the active routing table.
The floating static route remains inactive in the background and is only installed when the EIGRP prefix is removed due to network failure.

Anahtar Kavram

Floating Static Routes and Administrative Distance
Soru 1843Soru →

A network administrator needs to secure remote administrative access to a Cisco IOS switch by requiring users to authenticate against the local user database. Which two steps are required to implement local user database authentication for remote VTY line access? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Configure a local user account using the global configuration command 'username <name> secret <password>'.; Apply the line configuration command 'login local' under the VTY lines.

Cevap

To configure local user database authentication for remote VTY line access, you must define a local user account in global configuration mode using 'username <name> secret <password>' and configure 'login local' under the line configuration mode for VTY lines.
Local authentication requires both the creation of user credentials in the local security database using the global 'username' command and configuring the terminal lines (VTY) with 'login local' so Cisco IOS checks incoming connections against that database.

Adım Adım Çözüm

1
Define local user account
Local database contains valid credentials.
The system requires a defined user account stored in the local running-config database to check credentials against upon user connection.
2
Enable local authentication on line VTY mode
VTY lines prompt for username and password checked against local database.
By default, line configuration might look for simple line passwords or no password; 'login local' directs the line to check the username and password against the local device database.

Anahtar Kavram

Local User Database Authentication on Cisco IOS VTY Lines
Soru 1844Soru →

A network engineer is configuring Quality of Service (QoS) mechanisms on a Cisco router interface to control bandwidth usage. Which two behaviors are characteristic of traffic policing rather than traffic shaping? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Dropping excess packets immediately when traffic exceeds the configured rate limit; Remarking the DSCP or CoS values of out-of-profile traffic to lower priority values

Cevap

Traffic policing is characterized by dropping excess packets immediately when traffic exceeds the rate limit and remarking DSCP or CoS values of non-conforming packets.
Traffic policing enforces a hard rate limit by either dropping out-of-profile packets immediately or remarking their QoS headers (such as DSCP or CoS) to a lower priority class so they can be dropped downstream if congestion occurs.

Adım Adım Çözüm

1
Identify the key operational difference between policing and shaping
Policing acts on instantaneous traffic rates (inbound or outbound) by either dropping or remarking non-conforming packets.
Policers do not use memory buffers to hold excess traffic, whereas shapers buffer traffic to smooth bursts.
2
Evaluate the choices based on policing mechanics
Immediate packet drops and packet remarking are valid policing actions. Buffering packets and adding queuing delay describe shaping.
Shaping retains packets in a queue to smooth egress rate, while policing enforces strict rate boundaries.

Anahtar Kavram

Traffic Policing vs. Traffic Shaping Mechanics
Tahmini Süre:45s
Soru 1845Soru →

A network security engineering team is analyzing threat vectors affecting enterprise switch and router infrastructure. Match each security threat scenario on the left with its primary technical mitigation mechanism on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

An attacker transmits forged ARP responses on a campus VLAN to intercept traffic intended for the default gateway.
An attacker floods an edge router with high volumes of TCP SYN packets to exhaust CPU and control plane resources.
An unauthorized laptop connects to an unassigned Ethernet port in a conference room to gain access to internal subnet resources.
An attacker performs automated dictionary login attempts against exposed SSH remote management endpoints.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Forged ARP responses map to Dynamic ARP Inspection (DAI). Control plane TCP SYN flooding maps to Control Plane Policing (CoPP). Unauthorized wired switch port connection maps to 802.1X Port-Based Network Access Control. Automated SSH dictionary attacks map to Multi-Factor Authentication (MFA) and Rate Limiting.
Dynamic ARP Inspection checks ARP packets against trusted bindings to stop ARP poisoning. Control Plane Policing protects router processing resources by enforcing rate limits on traffic destined to the control plane. 802.1X enforces identity verification before opening switch port access. Multi-Factor Authentication combined with login rate limiting neutralizes automated password guessing.

Adım Adım Çözüm

1
Analyze Layer 2 address spoofing attacks on local switch subnets.
Identify ARP spoofing / poisoning as the threat vector.
Dynamic ARP Inspection intercepts and verifies invalid IP-to-MAC bindings using the DHCP snooping database.
2
Evaluate infrastructure plane threats targeting router CPU processing.
Identify control plane Denial-of-Service (DoS) exhaust attacks.
Control Plane Policing applies QoS policies directly to CPU-bound traffic queues to throttle malicious floods.
3
Examine physical access security and port-level network access control.
Identify unauthorized host connectivity on campus switch ports.
802.1X authenticates endpoints at Layer 2 before permitting traffic forwarding on the access switch port.
4
Assess administrative application threats targeting remote login services.
Identify credential harvesting and brute-force password attacks.
MFA ensures stolen or guessed passwords alone are insufficient, while rate limiting restricts high-frequency login attempts.

Anahtar Kavram

Classification of Network Security Threats and Primary Mitigation Controls
Tahmini Süre:2m 0s
Soru 1846Soru →

A network administrator is configuring static routes on router R1 to reach two remote networks: Subnet A (10.2.2.0/2410.2.2.0/24) connected across a point-to-point serial interface (Serial0/0/0), and Subnet B (10.3.3.0/2410.3.3.0/24) connected across a multiaccess Ethernet interface (GigabitEthernet0/0, with next-hop IP address 192.168.1.2192.168.1.2). Which two static route configuration commands follow Cisco IOS best practices and prevent unnecessary ARP resolution overhead?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ip route 10.2.2.0 255.255.255.0 Serial0/0/0; ip route 10.3.3.0 255.255.255.0 192.168.1.2

Cevap

The two correct static route statements are 'ip route 10.2.2.0 255.255.255.0 Serial0/0/0' for the point-to-point serial connection and 'ip route 10.3.3.0 255.255.255.0 192.168.1.2' for the multiaccess Ethernet connection.
In Cisco IOS IPv4 static routing, the ideal syntax depends on the physical media type of the outgoing interface. For point-to-point links like Serial interfaces, referencing the exit interface directly is complete and efficient because there is only one potential receiver on the segment. For broadcast multiaccess links like Ethernet, referencing the next-hop IPv4 address is mandatory for clean Layer 2 frame encapsulation without generating excessive ARP broadcasts.

Adım Adım Çözüm

1
Determine the interface media type for Subnet A (10.2.2.0/2410.2.2.0/24).
Subnet A uses a point-to-point serial link (Serial0/0/0).
On point-to-point links, specifying the local exit interface directly avoids next-hop IP recursive lookups without causing Layer 2 MAC resolution issues.
2
Determine the interface media type for Subnet B (10.3.3.0/2410.3.3.0/24).
Subnet B uses a broadcast multiaccess Ethernet link (GigabitEthernet0/0).
On Ethernet networks, specifying the next-hop IPv4 address (192.168.1.2192.168.1.2) allows the router to resolve the specific next-hop gateway MAC address, preventing proxy ARP overhead.
3
Verify Cisco IOS syntax compliance.
Confirm standard dotted-decimal subnet mask formatting (255.255.255.0).
Cisco IOS static routes mandate subnet masks ('ip route <prefix> <mask> {ip-address | exit-interface}').

Anahtar Kavram

IPv4 Static Route Syntax and Next-Hop Resolution on Point-to-Point vs Multiaccess Interfaces
Soru 1847Soru →

Two Cisco routers, R1 and R2, are directly connected via their GigabitEthernet0/0 interfaces on the 192.168.12.0/24 network segment. OSPFv2 is initialized on both routers. R1 has its GigabitEthernet0/0 interface placed into OSPF Area 0, while R2 has its GigabitEthernet0/0 interface placed into OSPF Area 10. All other OSPF interface configurations use default settings. What will be the observed result when an administrator executes the command `show ip ospf neighbor` on R1?

Cevabı ve açıklamayı göster

Cevap: No neighbor entry for R2 will be displayed in the neighbor table.

Cevap

No neighbor entry for R2 will be displayed in the neighbor table because Hello packets containing mismatched OSPF Area IDs are dropped during initial packet processing.
For OSPF neighbors to form an adjacency, specific Hello packet fields must match between connected interfaces: Area ID, Subnet Mask, Hello and Dead intervals, and Authentication. When R1 receives Hello packets from R2 with Area ID 10 while R1 is configured in Area 0, R1 discards the packets. Because valid Hello packets are never processed, R1 does not initialize a neighbor data structure for R2, leaving the OSPF neighbor table completely empty.

Adım Adım Çözüm

1
Analyze OSPF Hello packet validation criteria
Identified that Area ID, Hello/Dead intervals, Subnet Mask (on broadcast networks), and Authentication parameters must match exactly between connected interfaces.
OSPF requires neighbor interfaces to share identical primary link configuration parameters before forming an adjacency.
2
Evaluate the effect of an Area ID mismatch
R1 (Area 0) receives Hello packets from R2 containing Area 10 and drops them immediately.
When a received OSPF Hello header contains an Area ID differing from the receiving interface's configured Area ID, the packet is invalidated.
3
Determine the resulting neighbor table state on R1
R1 does not record R2 in any OSPF state (Down/INIT/2-WAY/FULL).
Without processing incoming Hello packets, R1 never discovers R2, resulting in no entry in `show ip ospf neighbor`.

Anahtar Kavram

OSPFv2 Hello Packet Parameter Matching for Neighbor Adjacency
Tahmini Süre:1m 15s
Soru 1848Soru →

A network administrator needs to restrict syslog messages sent to an external syslog server. The requirements specify that the remote server must receive only events with a severity level of Warning (level 4) and more critical events (levels 0 through 3), while excluding Notification (level 5), Informational (level 6), and Debugging (level 7) messages. Which Cisco IOS global configuration command meets this requirement?

Cevabı ve açıklamayı göster

Cevap: logging trap warnings

Cevap

The command 'logging trap warnings' (or 'logging trap 4') limits forwarded syslog messages to severity level 4 (Warning) and higher criticality levels (0 through 3).
The correct command is 'logging trap warnings'. In Cisco IOS, the 'logging trap <level>' command sets the maximum numerical severity level forwarded to remote syslog collectors. Specifying 'warnings' (or level 4) captures Emergency (0), Alert (1), Critical (2), Error (3), and Warning (4) messages while ignoring less severe messages (levels 5–7).

Adım Adım Çözüm

1
Identify the target syslog logging destination
The target destination is a remote syslog server, which is controlled by the 'logging trap' command syntax in Cisco IOS.
The 'logging trap' command defines severity level thresholds specifically for messages sent to remote syslog hosts, whereas 'logging buffered' controls RAM logging.
2
Map the requested severity keyword/numerical level
Warning corresponds to syslog severity level 4.
Cisco IOS syslog severity levels run from 0 (Emergency) to 7 (Debugging). Severity level 4 is named 'warnings'.
3
Apply the Cisco IOS severity threshold rule
Configuring level 4 forwards levels 0, 1, 2, 3, and 4 to the remote host while dropping levels 5, 6, and 7.
In Cisco IOS logging, configuring a trap level includes messages equal to or lower in numeric value (more severe) than the configured threshold.

Anahtar Kavram

Syslog Severity Levels and Remote Host Trap Thresholds
Soru 1849Soru →

Four routers (R1, R2, R3, and R4) are connected to a shared Ethernet switch in OSPFv2 Area 0. R1 (Router ID 1.1.1.1, interface priority 1) boots up first and completes initialization. Next, R2 (Router ID 2.2.2.2, interface priority 1) boots up and joins the network segment. Several minutes later, R3 (Router ID 3.3.3.3, interface priority 255) and R4 (Router ID 4.4.4.4, interface priority 0) are booted up and added to the OSPF segment. Assuming no OSPF processes are restarted or cleared, which router serves as the Designated Router (DR) on this multiaccess segment?

Cevabı ve açıklamayı göster

Cevap: R1

Cevap

R1 remains the Designated Router (DR) because OSPF DR elections are non-preemptive.
OSPF DR/BDR elections are non-preemptive on broadcast multiaccess networks. Since R1 booted first and was elected Designated Router, it retains the DR role continuously regardless of new routers with higher priorities or higher Router IDs joining the network later.

Adım Adım Çözüm

1
Evaluate the boot order and initial election outcome
R1 boots first and becomes the DR. R2 boots second and becomes the BDR.
When R1 boots, no existing DR exists on the segment, so R1 assumes the DR role. R2 joins next and claims the vacant BDR role.
2
Analyze the impact of adding R3 and R4 to an operational segment
R3 and R4 form adjacencies but do not trigger a new DR election.
OSPF DR/BDR elections are non-preemptive. Once a DR and BDR are active on a broadcast multiaccess segment, newly added routers with higher priority or higher Router IDs will not preempt the current DR or BDR.
3
Determine the final DR role assignment
R1 maintains its role as DR.
Because R1 has not failed or restarted its OSPF process, it continues functioning as the active DR.

Anahtar Kavram

OSPFv2 DR/BDR Non-Preemption
Tahmini Süre:1m 30s
Soru 1850Soru →

A network administrator configures an IPv4 extended access control list (ACL) on a Cisco router interface to allow web traffic using the following command:

`access-list 100 permit tcp host 192.168.1.50 any eq 80`

No other ACL entries are configured on the router. What happens when host 192.168.1.50 sends an ICMP echo request (ping) packet through the interface where this ACL is applied?

Cevabı ve açıklamayı göster

Cevap: The ICMP packet is dropped because of the unwritten implicit deny statement at the end of the access control list.

Cevap

The ICMP packet is dropped because of the unwritten implicit deny statement at the end of the access control list.
All IPv4 ACLs on Cisco IOS devices end with an implicit 'deny ip any any' clause. When an ICMP echo request is processed against the rule `access-list 100 permit tcp host 192.168.1.50 any eq 80`, it fails to match because ICMP is a separate protocol from TCP. Because there are no further explicit permit rules, the packet matches the implicit deny clause and is dropped.

Adım Adım Çözüm

1
Evaluate the incoming packet against the configured explicit ACL statement.
The incoming packet is an ICMP echo request, whereas statement 100 permits only TCP traffic targeting port 80.
ACLs process rules sequentially from top to bottom.
2
Check for subsequent matching statements or default end-of-list processing behavior.
No additional permit statements exist, so the packet falls through to the invisible final rule: `deny ip any any`.
All Cisco IPv4 ACLs automatically append an implicit deny statement at the end.
3
Determine the final packet disposition.
The ICMP packet is dropped at the router interface.
Unmatched traffic is discarded by the implicit deny rule.

Anahtar Kavram

Access Control List (ACL) Implicit Deny Clause
Soru 1851Soru →

A network administrator is designing a high-availability default gateway architecture for VLAN 10 (subnet 10.1.10.0/24) using two Layer 3 distribution switches. Switch-1 is configured with physical interface IP address 10.1.10.2/24 and Switch-2 is configured with physical interface IP address 10.1.10.3/24. The administrator is evaluating protocol characteristics between HSRPv2 and VRRPv3. Which two statements correctly describe operational differences and IP addressing rules between these protocols? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: VRRPv3 allows the virtual IP address to match Switch-1's physical interface IP address (10.1.10.2), automatically designating Switch-1 as the IP address owner with a default priority of 255.; HSRPv2 sends control messages to the IPv4 multicast destination address 224.0.0.102, whereas VRRP (v2/v3) sends advertisement messages to the IPv4 multicast destination address 224.0.0.18.

Cevap

The two correct statements are: VRRPv3 allows the virtual IP address to match a physical interface IP address (designating that router as the IP address owner with priority 255), and HSRPv2 uses multicast destination 224.0.0.102 while VRRP uses 224.0.0.18.
VRRPv3 supports IP address ownership where the virtual IP address matches a router's physical interface IP address, automatically elevating its priority to 255 (the maximum). In addition, HSRPv2 uses multicast group address 224.0.0.102 for hello packets, while VRRP uses multicast address 224.0.0.18.

Adım Adım Çözüm

1
Analyze virtual IP assignment rules for HSRP vs VRRP
HSRP requires the virtual IP address to be distinct from all physical interface IP addresses assigned to routers in the group. VRRP allows IP address ownership, where the virtual IP matches a physical interface IP address and sets priority to 255.
Verifies whether IP ownership is supported in HSRP vs VRRP.
2
Verify multicast destination addresses for HSRPv2 and VRRP
HSRPv1 uses 224.0.0.2, HSRPv2 uses 224.0.0.102, and VRRP (both v2 and v3) uses 224.0.0.18.
Differentiates protocol transport mechanics across FHRP implementations.
3
Evaluate default preemption mechanisms
HSRP disables preemption by default (higher priority standby router will not take over active state without explicit configuration). VRRP enables preemption by default.
Eliminates incorrect claims regarding preemption defaults.

Anahtar Kavram

FHRP protocol differences: VRRP IP address ownership, HSRP virtual IP uniqueness requirements, protocol multicast addresses, and default preemption settings.
Soru 1852Soru →

Match each Cisco Layer 2 security feature or interface trust state on the left with its correct operational behavior or dependency on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Dynamic ARP Inspection (DAI)
DHCP Snooping Untrusted Interface
Port Security Sticky MAC Learning
DHCP Snooping Binding Database

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Dynamic ARP Inspection matches with validating ARP packets against IP-to-MAC mappings. DHCP Snooping Untrusted Interface matches with dropping unauthorized DHCP server responses. Port Security Sticky MAC Learning matches with adding dynamically learned MAC addresses to the running configuration. DHCP Snooping Binding Database matches with tracking IP, MAC, VLAN, and interface bindings.
Dynamic ARP Inspection operates by validating incoming ARP packets against trusted IP-to-MAC bindings stored in the DHCP snooping binding database. An untrusted DHCP snooping interface blocks incoming server response messages (OFFER/ACK) to prevent rogue DHCP server deployment. Port Security sticky MAC learning writes dynamically learned host MAC addresses directly into the running configuration. The DHCP Snooping Binding Database stores client IP, MAC, VLAN, and port associations which are referenced by security features like DAI.

Adım Adım Çözüm

1
Analyze Dynamic ARP Inspection (DAI) functionality
DAI inspects ARP packets on untrusted ports and compares their source MAC and IP against trusted database entries.
DAI mitigates ARP spoofing by verifying ARP packet payload integrity.
2
Analyze DHCP Snooping interface trust states
Untrusted ports only permit DHCP client requests (DISCOVER, REQUEST); server responses (OFFER, ACK) are dropped.
Access ports default to untrusted to prevent unauthorized rogue DHCP servers.
3
Analyze Port Security sticky MAC learning behavior
Learned MAC addresses are written to the running configuration under the interface context.
Sticky MAC allows automatic MAC learning while preserving learned entries across link resets without manual static entry.
4
Identify the role of the DHCP Snooping Binding Database
It holds the IP-MAC-VLAN-Port binding entries populated by DHCP ACK messages.
Other L2 security mechanisms like DAI rely on this database to validate packets.

Anahtar Kavram

Layer 2 Security Mechanisms and Dependencies (Port Security, DHCP Snooping, DAI)
Soru 1853Soru →

Network architects are evaluating packet encapsulation and routing mechanisms within a modern Cisco Software-Defined Access (SD-Access) fabric architecture. Which two statements correctly differentiate the operational capabilities and responsibilities of the underlay network versus the overlay network? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The underlay network provides underlying physical or logical IP connectivity between fabric nodes using standard routing protocols like OSPF, IS-IS, or BGP to reach Routing Locator (RLOC) addresses.; The overlay network uses VXLAN encapsulation to encapsulate Layer 2 frames and Layer 3 packets into UDP packets, decoupling virtual network topology from physical underlay IP addressing.

Cevap

The correct statements are that the underlay network provides underlying IP connectivity between fabric nodes using standard routing protocols (like OSPF or IS-IS) to reach RLOC addresses, and the overlay network uses VXLAN encapsulation to transport Layer 2/3 traffic inside UDP packets to decouple the virtual network topology from physical underlay addressing.
In software-defined network architectures such as Cisco SD-Access, the underlay consists of physical interconnects and IP routing protocols (e.g., OSPF, IS-IS) that ensure end-to-end IP reachability between fabric nodes (Routing Locators or RLOCs). The overlay runs on top of the underlay and uses VXLAN to encapsulate Layer 2 and Layer 3 traffic into UDP packets, abstracting client endpoints (EIDs) from physical topology and allowing virtual network segmentation using VNIs.

Adım Adım Çözüm

1
Analyze underlay responsibilities in SDN fabric architectures.
Identified that the underlay is the physical infrastructure running standard IP routing protocols (OSPF, IS-IS, BGP) to guarantee IP reachability between fabric devices (RLOCs).
The underlay serves purely as the transport network for outer IP packet headers.
2
Analyze overlay responsibilities in SDN fabric architectures.
Identified that the overlay uses tunnel encapsulation (VXLAN in SD-Access) to transport virtual network payloads over the underlay, providing network virtualization and mobility.
The overlay abstracts user networks (EIDs) from physical switch locations (RLOCs).
3
Evaluate intermediate underlay node behavior regarding packet inspection.
Confirmed that underlay devices inspect only outer IP headers, not inner VXLAN VNI headers or overlay payloads.
Underlay switches route based on outer destination RLOC IP addresses.

Anahtar Kavram

Underlay vs. Overlay architecture separation in SDN and Cisco SD-Access fabrics
Soru 1854Soru →

An administrator configures the following extended IPv4 access control list on a Cisco IOS router to control traffic between subnets:

ip access-list extended SECURE_ACCESS
10 deny tcp host 192.168.10.15 host 10.1.20.10 eq 22
20 permit tcp host 192.168.10.15 10.1.20.0 0.0.0.255 eq 80
30 permit tcp host 192.168.10.15 10.1.20.0 0.0.0.255 eq 443
40 permit icmp 192.168.10.0 0.0.0.255 host 10.1.20.254 echo

The access list is applied inbound on the interface facing the 192.168.10.0/24 subnet. Which TWO statements accurately describe how traffic will be processed by this access control list?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: SSH traffic initiated from host 192.168.10.15 destined for host 10.1.20.10 is explicitly denied by sequence 10.; ICMP echo requests sent from host 192.168.10.50 destined for host 10.1.20.10 are dropped due to the implicit deny at the end of the access list.

Cevap

The correct statements are that SSH traffic from host 192.168.10.15 to host 10.1.20.10 is explicitly denied by sequence 10, and ICMP echo requests from host 192.168.10.50 to host 10.1.20.10 are dropped due to the implicit deny clause.
SSH packets from 192.168.10.15 to 10.1.20.10 hit sequence 10 directly and are denied. Meanwhile, ICMP echo requests from 192.168.10.50 to 10.1.20.10 fail to match sequence 40 (which restricts the destination to 10.1.20.254) and are consequently dropped by the implicit deny at the end of the ACL.

Adım Adım Çözüm

1
Analyze sequence 10: 'deny tcp host 192.168.10.15 host 10.1.20.10 eq 22'
Matches TCP traffic originating from IP 192.168.10.15 destined for IP 10.1.20.10 on port 22 (SSH). This packet matches the first statement and is immediately denied.
Cisco ACLs process statements sequentially from top to bottom and stop at the first matching entry.
2
Analyze HTTP traffic from host 192.168.10.20 to 10.1.20.5 against sequence 20: 'permit tcp host 192.168.10.15 10.1.20.0 0.0.0.255 eq 80'
The source address is constrained by the 'host' keyword to 192.168.10.15 only. Host 192.168.10.20 does not match.
The 'host' modifier specifies a single IP address (/32 equivalent), not an entire subnet.
3
Analyze ICMP traffic from host 192.168.10.50 to 10.1.20.10 against sequence 40: 'permit icmp 192.168.10.0 0.0.0.255 host 10.1.20.254 echo'
Although the source subnet matches, the destination host is explicitly set to host 10.1.20.254. Traffic directed to 10.1.20.10 fails sequence 40.
Both source and destination criteria in an extended ACL statement must match for the rule to take effect.
4
Determine final ACL evaluation outcome for unmatched traffic
All packets that pass through sequence lines 10–40 without a match hit the default implicit 'deny ip any any' at the end of the ACL and are dropped.
Every IPv4 ACL in Cisco IOS has an unwritten implicit deny entry at the end of its structure.

Anahtar Kavram

Extended Access Control List Sequential Processing and Implicit Deny Mechanics
Soru 1855Soru →

An engineer is configuring secure remote management on a central router named Edge-Rtr1. The device has a valid hostname, an IP domain name configured, a 1024-bit RSA key pair generated, and a local administrator user defined in global configuration mode. The virtual terminal lines are configured with transport input ssh. However, when connecting via SSH from a remote client, the router prompts only for a password instead of requesting a username, causing all login attempts to fail. Which configuration change on Edge-Rtr1 resolves this issue?

Cevabı ve açıklamayı göster

Cevap: Apply the login local command under line vty configuration mode.

Cevap

Apply the login local command under line vty configuration mode to instruct the switch/router to authenticate against the local user database.
The correct answer specifies applying the 'login local' command under line vty configuration mode. When SSH is enabled, Cisco IOS requires an authentication source capable of verifying usernames and passwords. Standard 'login' only checks for a single line-level password. Applying 'login local' directs the VTY lines to validate incoming credentials against usernames created in the local database.

Adım Adım Çözüm

1
Analyze the reported authentication symptom
The router prompts only for a password without asking for a username.
By default, line vty uses standard line authentication ('login'), which expects a password configured directly on the line via the 'password' command rather than searching local user accounts.
2
Determine the required VTY configuration command
Adding 'login local' under line vty 0 4 binds authentication to the local running-config database.
SSH requires username-based authentication. Without 'login local' (or AAA), the VTY lines cannot process the username sent by the SSH client.

Anahtar Kavram

VTY Line Local Authentication Binding for SSH
Soru 1856Soru →

An administrator attempts to secure VLAN 20 on a Cisco Catalyst switch by executing the commands `ip dhcp snooping vlan 20` and `ip arp inspection vlan 20`. Access interface GigabitEthernet0/2 is in VLAN 20 and remains in its default untrusted state for both security features. Clients connected to GigabitEthernet0/2 are configured with static IP addresses, but all outgoing ARP packets from these clients are intercepted and dropped by the switch, preventing any network communication. Which root cause explains why Dynamic ARP Inspection (DAI) is dropping this ARP traffic?

Cevabı ve açıklamayı göster

Cevap: Global DHCP snooping was not activated using the `ip dhcp snooping` command, causing the DHCP binding database to remain unpopulated and DAI to reject all ARP packets on untrusted ports.

Cevap

Global DHCP snooping was not activated using the `ip dhcp snooping` command, preventing the switch from building the DHCP binding database required by Dynamic ARP Inspection (DAI) to validate ARP packets on untrusted ports.
The correct option explains that Dynamic ARP Inspection (DAI) depends directly on the DHCP snooping binding database to inspect ARP packets received on untrusted ports. Enabling DHCP snooping on a VLAN (`ip dhcp snooping vlan 20`) without executing the global `ip dhcp snooping` command leaves DHCP snooping globally disabled. As a result, the switch does not build a binding database. When DAI is enabled on VLAN 20 (`ip arp inspection vlan 20`), it intercepts all ARP packets on untrusted ports; because the binding table is empty and no ARP ACL is defined for static hosts, DAI drops all incoming ARP packets.

Adım Adım Çözüm

1
Analyze how Dynamic ARP Inspection (DAI) validates ARP packets.
DAI inspects incoming ARP requests and responses on untrusted ports and verifies the sender IP and MAC addresses against the DHCP Snooping Binding Database (or configured ARP ACLs).
Untrusted ports drop ARP packets if no corresponding IP-to-MAC entry exists in the binding table.
2
Evaluate the switch configuration sequence provided in the scenario.
The administrator configured `ip dhcp snooping vlan 20`, but omitted the global `ip dhcp snooping` command.
In Cisco IOS, VLAN-level DHCP snooping does not take effect unless DHCP snooping is enabled globally.
3
Determine the impact on static IP hosts on untrusted ports.
Because global DHCP snooping is disabled, no DHCP binding database is built. Additionally, statically assigned hosts generate no DHCP transactions to populate the database.
Without static ARP ACL mappings or an active DHCP binding database entry, DAI drops all ARP traffic on untrusted interfaces like GigabitEthernet0/2.

Anahtar Kavram

Dynamic ARP Inspection (DAI) reliance on the DHCP Snooping Binding Database and global feature enablement prerequisites.
Soru 1857Soru →

An enterprise network engineer is using Cisco DNA Center Software Image Management (SWIM) to upgrade the Cisco IOS XE operating system across a cluster of access switches. The engineer imports the required software image into the Cisco DNA Center repository, marks it as the Golden Image for the switch family, and schedules the deployment. Cisco DNA Center successfully transfers the image file to the local flash storage of all target switches during the maintenance window. However, after the task finishes, all switches continue to run their previous operating system version and Cisco DNA Center flags the switches as non-compliant.

Which phase of the SWIM workflow was omitted or failed to execute?

Cevabı ve açıklamayı göster

Cevap: The image Activation step was not performed, leaving the switch boot variables pointed to the legacy software image file.

Cevap

The image Activation step was not performed, leaving the switch boot variables pointed to the legacy software image file.
The Cisco DNA Center SWIM workflow separates file transfer from system update. The Distribution phase transfers the software image file into the flash memory of the managed device. To complete the upgrade, the Activation phase must be executed. Activation alters the device boot options, performs pre-upgrade checks, reloads the switch into the new software image, and verifies post-upgrade health.

Adım Adım Çözüm

1
Analyze the Cisco DNA Center SWIM lifecycle stages
Identify that SWIM consists of distinct stages: Import Image -> Mark as Golden -> Check Compliance -> Distribute Image -> Activate Image.
Understanding the separation between transferring files and applying images is essential for controller-based network management.
2
Evaluate the state of the switches in the scenario
The image was successfully copied to flash (Distribution completed), but the running software version did not change.
File transfer to flash memory does not automatically alter device boot environment variables or trigger a system reload.
3
Determine the missing required operation
Activation must be triggered in Cisco DNA Center to change boot statements, perform pre-checks, execute the reboot, and conduct post-activation verification.
Without Activation, the device reboots into (or remains running) the existing software version.

Anahtar Kavram

Cisco DNA Center Software Image Management (SWIM) Workflow
Soru 1858Soru →

An network engineer issues a REST API call to a Cisco DNA Center controller to retrieve information regarding managed network devices. The controller returns the following JSON response payload:

{
"response": [
{
"family": "Switches and Hubs",
"hostname": "Dist-Switch-01",
"managementIpAddress": "192.168.10.1",
"upTime": "12 days, 04:12:00",
"interfaceList": [
{
"portName": "GigabitEthernet1/0/1",
"vlan": 10,
"status": "up",
"speed": 1000
},
{
"portName": "GigabitEthernet1/0/2",
"vlan": 20,
"status": "down",
"speed": 1000
}
]
},
{
"family": "Routers",
"hostname": "Edge-Router-01",
"managementIpAddress": "10.1.1.1",
"upTime": "45 days, 11:05:22",
"interfaceList": [
{
"portName": "GigabitEthernet0/0/0",
"vlan": 1,
"status": "up",
"speed": 10000
}
]
}
],
"version": "1.0"
}

Assuming the variable `data` holds the parsed Python dictionary representation of this JSON payload, which Python expression correctly extracts the operating status (`"status"`) of the second interface on the distribution switch (`Dist-Switch-01`)?

Cevabı ve açıklamayı göster

Cevap: data["response"][0]["interfaceList"][1]["status"]

Cevap

data["response"][0]["interfaceList"][1]["status"]
The top-level JSON structure is an object mapped to a Python dictionary containing the key 'response'. The value of 'response' is a list of device objects. The distribution switch ('Dist-Switch-01') is the first element in this list, which corresponds to index 0. Within this dictionary, 'interfaceList' holds a list of interface objects. The second interface ('GigabitEthernet1/0/2') is located at index 1 of this list. Accessing the key 'status' on this dictionary yields the desired value.

Adım Adım Çözüm

1
Identify the top-level structure and navigate to the 'response' array
The top-level JSON element is an object (dictionary). Accessing data["response"] returns a list containing two device dictionary objects.
Top-level JSON curly braces {} map to a Python dictionary where keys are string names.
2
Select the distribution switch object from the 'response' array using zero-based indexing
The distribution switch ('Dist-Switch-01') is the first item in the list, accessed via index 0: data["response"][0].
JSON square brackets [] map to Python lists, which use zero-based indexing (0 is the 1st item).
3
Navigate to the 'interfaceList' key within the distribution switch dictionary
Accessing data["response"][0]["interfaceList"] returns a list of interface dictionaries.
The key 'interfaceList' inside the device object points to an array of interface dictionaries.
4
Select the second interface and extract the 'status' key value
The second interface ('GigabitEthernet1/0/2') is at index 1 of the list, and its status is extracted via data["response"][0]["interfaceList"][1]["status"].
The second element in a zero-indexed array has an index of 1.

Anahtar Kavram

Interpreting JSON Encoded Data and Accessing Nested Data Structures
Tahmini Süre:1m 30s
Soru 1859Soru →

A network engineering team implements an automated, controller-led management model to enforce baseline configurations across 200 edge routers. Instead of manually pushing changes via device-by-device CLI scripts, the team defines target configurations in centralized declarative state files. Which operational benefit is primarily realized by adopting this automated approach?

Cevabı ve açıklamayı göster

Cevap: Device configurations are continuously aligned with a centralized intent model, reducing configuration drift and operational errors.

Cevap

Device configurations are continuously aligned with a centralized intent model, reducing configuration drift and operational errors.
Automated network management leveraging declarative state models ensures that network devices match a predefined single source of truth. The controller or automation engine automatically reconciles discrepancies, which eliminates configuration drift, reduces manual intervention, and lowers the risk of human error during large-scale network changes.

Adım Adım Çözüm

1
Analyze the operational shift from manual per-device CLI changes to centralized declarative automation.
Manual CLI changes are prone to syntax mistakes, human error, and subtle variations between devices known as configuration drift.
Declarative state files describe what the final network configuration should be rather than detailing the sequence of steps to execute.
2
Evaluate how controller-based declarative management maintains network integrity.
The central management platform checks current device state against the declared baseline state and automatically applies necessary changes to achieve compliance.
This guarantees consistent state enforcement and drastically minimizes configuration drift across enterprise devices.

Anahtar Kavram

Declarative Configuration Management and Drift Reduction
Tahmini Süre:1m 15s
Soru 1860Soru →

In Cisco DNA Center, Software Image Management (SWIM) simplifies the maintenance of device software binaries across enterprise networks. What is the primary purpose of designating a software image as a 'Golden Image' within SWIM?

Cevabı ve açıklamayı göster

Cevap: It defines the software version as the baseline standard for a specific device family, enabling Cisco DNA Center to identify non-compliant devices.

Cevap

Designating a software image as a 'Golden Image' in Cisco DNA Center SWIM establishes that image as the approved baseline standard for a specific device model or role, allowing the controller to report compliance status.
Designating a software image as a 'Golden Image' within Cisco DNA Center Software Image Management (SWIM) establishes it as the standard, approved software version for a specified device family or role. Once tagged, Cisco DNA Center compares devices against this baseline to highlight software version drift and compliance status.

Adım Adım Çözüm

1
Identify the primary function of Software Image Management (SWIM) in Cisco DNA Center.
SWIM manages software image repositories, checks device compliance, and handles image distribution and activation.
Understanding the core repository functionality helps distinguish image baselining from active deployment tasks.
2
Analyze the role of 'Golden Image' designation within the SWIM workflow.
A Golden Image is assigned to specific device families or roles as the network administrator's validated software standard.
Defining a baseline allows Cisco DNA Center to automatically compare running software versions against the Golden Image and flag non-compliant devices.

Anahtar Kavram

Cisco DNA Center Software Image Management (SWIM) Golden Image Baselines
Tahmini Süre:45s
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