Prueba del protocolo de resolución de direcciones / Módulo 8 - 8.4.2
Pregunta 1
How does the ARP process use an IP address?
• ❌ To determine the MAC address of the remote destination host
• ✅ To determine the MAC address of a device on the same network
• ❌ To determine the amount of time a packet takes when traveling from source to destination
• ❌ To determine the network number based on the number of bits in the IP address
Explicación:
ARP se utiliza para mapear una dirección IP a una dirección MAC dentro de la misma red local (LAN), no para dispositivos remotos.Pregunta 2
What will a host do first when preparing a Layer 2 PDU for transmission to a host on the same Ethernet network?
• ❌ It will send the PDU to the router directly connected to the network.
• ❌ It will query the local DNS server for the name of the destination host.
• ✅ It will search the ARP table for the MAC address of the destination host.
• ❌ It will initiate an ARP request to find the MAC address of the destination host.
Explicación:
Primero se revisa la tabla ARP. Solo si no se encuentra una entrada válida, se genera una solicitud ARP.Pregunta 3
Refer to the exhibit. Which protocol was responsible for building the table that is shown?
• ❌ DHCP
• ❌ DNS
• ✅ ARP
• ❌ ICMP
Explicación:
La tabla mostrada con direcciones IP y MAC es creada por el protocolo ARP.Pregunta 4
When an IP packet is sent to a host on a remote network, what information is provided by ARP?
• ❌ The IP address of the destination host
• ❌ The IP address of the default gateway
• ✅ The MAC address of the router interface closest to the sending host
• ❌ The MAC address of the switch port that connects to the sending host
Explicación:
Cuando se envía a una red remota, el paquete va hacia el gateway. ARP obtiene la dirección MAC del gateway.Pregunta 5
A host is trying to send a packet to a device on a remote LAN segment, but there are currently no mappings in the ARP cache. How will the device obtain a destination MAC address?
• ❌ It will send an ARP request for the MAC address of the destination device.
• ✅ It will send an ARP request for the MAC address of the default gateway.
• ❌ It will send the frame and use the device MAC address as the destination.
• ❌ It will send the frame with a broadcast MAC address.
• ❌ It will send an ARP request to the DNS server for the destination MAC address.
Explicación:
En una red remota, el host necesita la MAC del gateway para enviar el paquete. Por eso hace ARP al router.Pregunta 6
What is the aim of an ARP spoofing attack?
• ❌ To flood the network with ARP reply broadcasts
• ❌ To fill switch MAC address tables with bogus addresses
• ✅ To associate IP addresses to the wrong MAC address
• ❌ To overwhelm network hosts with ARP requests
Explicación:
ARP spoofing manipula la tabla ARP para que una IP legítima apunte a una MAC falsa.Pregunta 7
A host needs to reach another host on a remote network, but the ARP cache has no mapping entries. To what destination address will the host send an ARP request?
• ❌ The unicast IP address of the remote host
• ❌ The unicast MAC address of the remote host
• ❌ The subnet broadcast IP address
• ✅ The broadcast MAC address
Explicación:
ARP requests siempre se envían a la dirección MAC de broadcast (FF:FF:FF:FF:FF:FF).
Pregunta 8
Refer to the exhibit. PC1 issues an ARP request because it needs to send a packet to PC2. In this scenario, what will happen next?
• ✅ PC2 will send an ARP reply with the PC2 MAC address.
• ❌ RT1 will send an ARP reply with the RT1 Fa0/0 MAC address.
• ❌ RT1 will send an ARP reply with the PC2 MAC address.
• ❌ SW1 will send an ARP reply with the PC2 MAC address.
• ❌ SW1 will send an ARP reply with the SW1 Fa0/1 MAC address.
Explicación:
El host de destino (PC2) responde con su dirección MAC en respuesta al ARP.Pregunta 9
In what kind of memory is the ARP table stored on a device?
• ❌ Flash
• ✅ RAM
• ❌ ROM
• ❌ NVRAM
Explicación:
La tabla ARP se guarda en la RAM, ya que se llena dinámicamente y se borra al reiniciar.Pregunta 10
What is a characteristic of ARP messages?
• ❌ ARP requests are broadcasts, and they are flooded out all ports by the switch.
• ❌ ARP messages are encapsulated within an IPv4 header.
• ❌ ARP messages have a type field of 0x805.
• ✅ ARP replies are unicast.
Explicación:
Las solicitudes ARP son broadcast, pero las respuestas ARP se envían directamente (unicast) al solicitante.Pregunta 11
What statement describes the function of the Address Resolution Protocol?
• ❌ ARP is used to discover the IP address of any host on a different network.
• ❌ ARP is used to discover the IP address of any host on the local network.
• ❌ ARP is used to discover the MAC address of any host on a different network.
• ✅ ARP is used to discover the MAC address of any host on the local network.
Explicación:
ARP solo funciona dentro de una red local para resolver direcciones IP en direcciones MAC.Pregunta 12
Why would an attacker want to spoof a MAC address?
• ✅ So that a switch on the LAN will start forwarding frames to the attacker instead of to the legitimate host
• ❌ So that a switch on the LAN will start forwarding all frames toward the device that is under control of the attacker (that can then capture the LAN traffic)
• ❌ So that the attacker can capture traffic from multiple VLANs rather than from just the VLAN that is assigned to the port to which the attacker device is attached
• ❌ So that the attacker can launch another type of attack in order to gain access to the switch
Explicación:
Un atacante puede suplantar (spoof) una dirección MAC para hacerse pasar por un dispositivo legítimo en la red. Esto engaña al switch, que comenzará a enviar los frames destinados al dispositivo original hacia el atacante, permitiéndole interceptar o modificar datos.Pregunta 13
What important information is examined in the Ethernet frame header by a Layer 2 device in order to forward the data onward?
• ✅ Destination MAC address
• ❌ Source MAC address
• ❌ Source IP address
• ❌ Ethernet type
• ❌ Destination IP address
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