CCNA 1 v7 Modules 8 – 10: Communicating Between Networks
This flashcard set focuses on key networking concepts such as IP addressing, routing behavior, packet forwarding, and OSI model functions. It covers how routers make forwarding decisions, the role of default gateways, IPv6 advantages over IPv4, and essential services provided by the network layer to ensure efficient data delivery across networks.
Which information is used by routers to forward a data packet toward its destination?
source IP address
destination IP address
source data-link address
destination data-link address
destination IP address
Key Terms
Which information is used by routers to forward a data packet toward its destination?
source IP address
destination IP address
source data-link address
destination data-link address
destination IP address
A computer has to send a packet to a destination host in the same LAN. How will the packet be sent?
The packet will be sent to the default gateway first, and then, depending on the response from the gateway, it may be sent to the destination host.
The packet will be sent directly to the destination host.
The packet will first be sent to the default gateway, and then from the default gateway it will be sent directly to the destination host.
The packet will be sent only to the default gateway.
The packet will be sent directly to the destination host.
A router receives a packet from the Gigabit 0/0 interface and determines that the packet needs to be forwarded out the Gigabit 0/1 interface. What will the router do next?
route the packet out the Gigabit 0/1 interface
create a new Layer 2 Ethernet frame to be sent to the destination
look into the ARP cache to determine the destination IP address
look into the routing table to determine if the destination network is in the routing table
create a new Layer 2 Ethernet frame to be sent to the destination
Which IPv4 address can a host use to ping the loopback interface?
126.0.0.1
127.0.0.0
126.0.0.0
127.0.0.1
127.0.0.1
A computer can access devices on the same network but cannot access devices on other networks. What is the probable cause of this problem?
The cable is not connected properly to the NIC.
The computer has an invalid IP address.
The computer has an incorrect subnet mask.
The computer has an invalid default gateway address.
The computer has an invalid default gateway address.
Which parameter does the router use to choose the path to the destination when there are multiple routes available?
the lower metric value that is associated with the destination network
the lower gateway IP address to get to the destination network
the higher metric value that is associated with the destination network
the higher gateway IP address to get to the destination network
the lower metric value that is associated with the destination network
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Which information is used by routers to forward a data packet toward its destination? source IP address | destination IP address |
A computer has to send a packet to a destination host in the same LAN. How will the packet be sent? The packet will be sent to the default gateway first, and then, depending on the response from the gateway, it may be sent to the destination host. | The packet will be sent directly to the destination host. |
A router receives a packet from the Gigabit 0/0 interface and determines that the packet needs to be forwarded out the Gigabit 0/1 interface. What will the router do next? route the packet out the Gigabit 0/1 interface | create a new Layer 2 Ethernet frame to be sent to the destination |
Which IPv4 address can a host use to ping the loopback interface? 126.0.0.1 | 127.0.0.1 |
A computer can access devices on the same network but cannot access devices on other networks. What is the probable cause of this problem? The cable is not connected properly to the NIC. | The computer has an invalid default gateway address. |
Which parameter does the router use to choose the path to the destination when there are multiple routes available? the lower metric value that is associated with the destination network | the lower metric value that is associated with the destination network |
Which statement describes a feature of the IP protocol? IP encapsulation is modified based on network media. | IP relies on upper layer services to handle situations of missing or out-of-order packets. Explanation: IP protocol is a connection-less protocol, considered unreliable in terms of end-to-end delivery. It does not provide error control in the cases where receiving packets are out-of-order or in cases of missing packets. It relies on upper layer services, such as TCP, to resolve these issues. |
Why is NAT not needed in IPv6? Because IPv6 has integrated security, there is no need to hide the IPv6 addresses of internal networks. | Any host or user can get a public IPv6 network address because the number of available IPv6 addresses is extremely large. Explanation: The large number of public IPv6 addresses eliminates the need for NAT. Sites from the largest enterprises to single households can get public IPv6 network addresses. This avoids some of the NAT-induced application problems that are experienced by applications that require end-to-end connectivity. |
Within a production network, what is the purpose of configuring a switch with a default gateway address? Hosts that are connected to the switch can use the switch default gateway address to forward packets to a remote destination. | The default gateway address is used to forward packets originating from the switch to remote networks. Explanation: A default gateway address allows a switch to forward packets that originate on the switch to remote networks. A default gateway address on a switch does not provide Layer 3 routing for PCs that are connected on that switch. A switch can still be accessible from Telnet as long as the source of the Telnet connection is on the local network. |
What are two services provided by the OSI network layer? (Choose two.) performing error detection | routing packets toward the destination Explanation: The OSI network layer provides several services to allow communication between devices: addressing |
What IPv4 header field identifies the upper layer protocol carried in the packet? Protocol | Protocol Explanation: It is the Protocol field in the IP header that identifies the upper-layer protocol the packet is carrying. The Version field identifies the IP version. The Differential Services field is used for setting packet priority. The Identification field is used to reorder fragmented packets. |
Which field in the IPv4 header is used to prevent a packet from traversing a network endlessly? Time-to-Live | Time-to-Live Explanation: The value of the Time-to-Live (TTL) field in the IPv4 header is used to limit the lifetime of a packet. The sending host sets the initial TTL value; which is decreased by one each time the packet is processed by a router. If the TTL field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address. The Differentiated Services (DS) field is used to determine the priority of each packet. Sequence Number and Acknowledgment Number are two fields in the TCP header. |
What is a basic characteristic of the IP protocol? connectionless | connectionless Explanation: Internet Protocol (IP) is a network layer protocol that does not require initial exchange of control information to establish an end-to-end connection before packets are forwarded. Thus, IP is connectionless and does not provide reliable end-to-end delivery by itself. IP is media independent. User data segmentation is a service provided at the transport layer. |
What is one advantage that the IPv6 simplified header offers over IPv4? smaller-sized header | efficient packet handling Explanation: The IPv6 simplified header offers several advantages over IPv4: Better routing efficiency and efficient packet handling for performance and forwarding-rate scalability |
What information does the loopback test provide? The TCP/IP stack on the device is working correctly. | The TCP/IP stack on the device is working correctly. Explanation: Because the loopback test sends packets back to the host device, it does not provide information about network connectivity to other hosts. The loopback test verifies that the host NIC, drivers, and TCP/IP stack are functioning. |
What routing table entry has a next hop address associated with a destination network? directly-connected routes | remote routes Explanation: Routing table entries for remote routes will have a next hop IP address. The next hop IP address is the address of the router interface of the next device to be used to reach the destination network. Directly-connected and local routes have no next hop, because they do not require going through another router to be reached. |
How do hosts ensure that their packets are directed to the correct network destination? They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route. | They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route. Explanation: Hosts must maintain their own local routing table to ensure that network layer packets are directed to the correct destination network. This local table typically contains a route to the loopback interface, a route to the network that the host is connected to, and a local default route, which represents the route that packets must take to reach all remote network addresses. |
When transporting data from real-time applications, such as streaming audio and video, which field in the IPv6 header can be used to inform the routers and switches to maintain the same path for the packets in the same conversation? Next Header | Flow Label Explanation: The Flow Label in IPv6 header is a 20-bit field that provides a special service for real-time applications. This field can be used to inform routers and switches to maintain the same path for the packet flow so that packets will not be reordered. |
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 MAC address of any host on the local network. Explanation: When a PC wants to send data on the network, it always knows the IP address of the destination. However, it also needs to discover the MAC address of the destination. ARP is the protocol that is used to discover the MAC address of a host that belongs to the same network. |
Under which two circumstances will a switch flood a frame out of every port except the port that the frame was received on? (Choose two.) The frame has the broadcast address as the destination address. | The frame has the broadcast address as the destination address. Explanation: A switch will flood a frame out of every port, except the one that the frame was received from, under two circumstances. Either the frame has the broadcast address as the destination address, or the destination address is unknown to the switch. |
Which statement describes the treatment of ARP requests on the local link? They must be forwarded by all routers on the local network. | They are received and processed by every device on the local network. Explanation: One of the negative issues with ARP requests is that they are sent as a broadcast. This means all devices on the local link must receive and process the request. |
Which destination address is used in an ARP request frame? 0.0.0.0 | FFFF.FFFF.FFFF Explanation: The purpose of an ARP request is to find the MAC address of the destination host on an Ethernet LAN. The ARP process sends a Layer 2 broadcast to all devices on the Ethernet LAN. The frame contains the IP address of the destination and the broadcast MAC address, FFFF.FFFF.FFFF. The host with the IP address that matches the IP address in the ARP request will reply with a unicast frame that includes the MAC address of the host. Thus the original sending host will obtain the destination IP and MAC address pair to continue the encapsulation process for data transmission. |
A network technician issues the arp -d * command on a PC after the router that is connected to the LAN is reconfigured. What is the result after this command is issued? The ARP cache is cleared. | The ARP cache is cleared. Explanation: Issuing the arp –d * command on a PC will clear the ARP cache content. This is helpful when a network technician wants to ensure the cache is populated with updated information. |
Refer to the exhibit. The exhibit shows a small switched network and the contents of the MAC address table of the switch. PC1 has sent a frame addressed to PC3. What will the switch do with the frame? The switch will discard the frame. | The switch will forward the frame to all ports except port 4. Explanation: The MAC address of PC3 is not present in the MAC table of the switch. Because the switch does not know where to send the frame that is addressed to PC3, it will forward the frame to all the switch ports, except for port 4, which is the incoming port. |
Which two types of IPv6 messages are used in place of ARP for address resolution? anycast | neighbor solicitation Explanation: IPv6 does not use ARP. Instead, ICMPv6 neighbor discovery is used by sending neighbor solicitation and neighbor advertisement messages. |
What is the aim of an ARP spoofing attack? to flood the network with ARP reply broadcasts | to associate IP addresses to the wrong MAC address Explanation: In an ARP spoofing attack, a malicious host intercepts ARP requests and replies to them so that network hosts will map an IP address to the MAC address of the malicious host. |
Where are IPv4 address to Layer 2 Ethernet address mappings maintained on a host computer? neighbor table | ARP cache Explanation: The ARP cache is used to store IPv4 addresses and the Ethernet physical addresses or MAC addresses to which the IPv4 addresses are mapped. Incorrect mappings of IP addresses to MAC addresses can result in loss of end-to-end connectivity. |
What important information is examined in the Ethernet frame header by a Layer 2 device in order to forward the data onward? source MAC address | destination MAC address Explanation: The Layer 2 device, such as a switch, uses the destination MAC address to determine which path (interface or port) should be used to send the data onward to the destination device. |
A new network administrator has been asked to enter a banner message on a Cisco device. What is the fastest way a network administrator could test whether the banner is properly configured? Reboot the device. | Exit privileged EXEC mode and press Enter. |
What are two functions of NVRAM? (Choose two.) to store the routing table | to retain contents when power is removed |
A router boots and enters setup mode. What is the reason for this? The IOS image is corrupt. | The configuration file is missing from NVRAM. |
The global configuration command ip default-gateway 172.16.100.1 is applied to a switch. What is the effect of this command? The switch will have a management interface with the address 172.16.100.1. | The switch can be remotely managed from a host on another network. |
What happens when the transport input ssh command is entered on the switch vty lines? The SSH client on the switch is enabled. | Communication between the switch and remote users is encrypted. |
Refer to the exhibit. A user PC has successfully transmitted packets to www.cisco.com. Which IP address does the user PC target in order to forward its data off the local network? | 172.20.0.254 |
Which three commands are used to set up secure access to a router through a connection to the console interface? (Choose three.) interface fastethernet 0/0 | line console 0 |
Which two functions are primary functions of a router? (Choose two.) packet forwarding | packet forwarding |
What is the effect of using the Router# copy running-config startup-config command on a router? The contents of ROM will change. | The contents of NVRAM will change. |
What will happen if the default gateway address is incorrectly configured on a host? The host cannot communicate with other hosts in the local network. | The host cannot communicate with hosts in other networks. |
What are two potential network problems that can result from ARP operation? (Choose two.) Manually configuring static ARP associations could facilitate ARP poisoning or MAC address spoofing. | On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays. |
Open the PT activity. Perform the tasks in the activity instructions and then answer the question. Which interfaces in each router are active and operational? R1: G0/1 and S0/0/1 R1: G0/0 and S0/0/0 R1: G0/0 and S0/0/1 | R1: G0/0 and S0/0/0 |
Which term describes a field in the IPv4 packet header used to identify the next level protocol? protocol | protocol |
Which term describes a field in the IPv4 packet header that contains an 8-bit binary value used to determine the priority of each packet? differentiated services | differentiated services |
Which term describes a field in the IPv4 packet header that contains a 32-bit binary value associated with an interface on the sending device? source IPv4 address | source IPv4 address |
Which term describes a field in the IPv4 packet header used to detect corruption in the IPv4 header? header checksum | header checksum |
RTR1(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Payroll LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 10.27.14.148 | 10.27.14.148 |
Which term describes a field in the IPv4 packet header that contains a unicast, multicast, or broadcast address? destination IPv4 address | destination IPv4 address |
Which term describes a field in the IPv4 packet header used to limit the lifetime of a packet? TTL | TTL |
Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100? version | version |
Which term describes a field in the IPv4 packet header used to identify the next level protocol? protocol | protocol |
Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100? version | version |
What property of ARP causes cached IP-to-MAC mappings to remain in memory longer? Entries in an ARP table are time-stamped and are purged after the timeout expires. | Entries in an ARP table are time-stamped and are purged after the timeout expires |
What property of ARP allows MAC addresses of frequently used servers to be fixed in the ARP table? A static IP-to-MAC address entry can be entered manually into an ARP table. | A static IP-to-MAC address entry can be entered manually into an ARP table. |
What property of ARP allows MAC addresses of frequently used servers to be fixed in the ARP table? A static IP-to-MAC address entry can be entered manually into an ARP table. | A static IP-to-MAC address entry can be entered manually into an ARP table. |
What property of ARP allows hosts on a LAN to send traffic to remote networks? Local hosts learn the MAC address of the default gateway. | Local hosts learn the MAC address of the default gateway. |
Floor(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Registrar LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 192.168.235.234 | 192.168.235.234 |
What property of ARP forces all Ethernet NICs to process an ARP request? The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. | The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. |
What property of ARP causes a reply only to the source sending an ARP request? The source MAC address appears in the header of the Ethernet frame. | The source MAC address appears in the header of the Ethernet frame. |
What property of ARP causes the request to be flooded out all ports of a switch except for the port receiving the ARP request? The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. | The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. |
What property of ARP causes the NICs receiving an ARP request to pass the data portion of the Ethernet frame to the ARP process? The type field 0x806 appears in the header of the Ethernet frame. | The type field 0x806 appears in the header of the Ethernet frame. |
What property of ARP causes the NICs receiving an ARP request to pass the data portion of the Ethernet frame to the ARP process? The type field 0x806 appears in the header of the Ethernet frame. | The type field 0x806 appears in the header of the Ethernet frame. |
Main(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Service LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 172.29.157.156 | 172.29.157.156 |
BldgA(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Medical LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 192.168.191.189 | 192.168.191.189 |
Floor(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Registrar LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 192.168.225.223 | 192.168.225.223 |
Floor(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Manager LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 10.118.62.196 | 10.118.62.196 |
HQ(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Store LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 172.19.98.230 | 172.19.98.230 |
HQ(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Store LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 172.20.132.13 | 172.20.132.13 |
Main(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Service LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 192.168.167.166 | 192.168.167.166 |
BldgA(config)# interface gi0/1 Refer to the exhibit. A network administrator is connecting a new host to the Medical LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host? 192.168.201.200 | 192.168.201.200 |