Chapter 7 Routing

What is the primary function of a router in an IP network?
A) Interconnect network IDs and filter/forward packets based on IP address.
B) Connect devices within a LAN and filter/forward based on MAC address.
C) Provide wireless access to clients and manage SSIDs.
D) Encrypt traffic between hosts on the same broadcast domain.

A — Interconnect network IDs and filter/forward packets based on IP address.

What is the main difference between a switch and a router?
A) Switches filter/forward based on MAC addresses; routers filter/forward based on IP addresses.
B) Switches operate at Layer 3; routers operate at Layer 2.
C) Switches require at least two interfaces; routers require one.
D) Switches perform ARP for remote networks; routers broadcast for all hosts.

A — Switches filter/forward based on MAC addresses; routers filter/forward based on IP addresses.

How many network connections must a router have at minimum to function as a router?
A) One
B) Two
C) Three
D) Four

B — Two

In a routing table, what does an entry with destination 0.0.0.0 and subnet 0.0.0.0 usually represent?
A) A directly connected network route.
B) A host route for a specific IP.
C) The default route (send here if no other match).
D) A multicast route.

C — The default route (send here if no other match).

If a router has a directly connected route to 232.25.201.0/24 and receives a packet for 232.25.201.66, what does it do to deliver the packet?
A) It looks up an upstream default gateway and forwards the packet there without ARP.
B) It ARPs the destination on that interface to get the MAC address and sends the frame out that interface.
C) It modifies the destination IP and sends it to the internet.
D) It drops the packet because it's outside the local network.

B — It ARPs the destination on that interface to get the MAC address and sends the frame out that interface.

When a router has two default routes (e.g., one via cable and one via DSL), how does it decide which to use?
A) It chooses the interface with the highest MAC address.
B) It uses the metric value; the route with the lower metric is preferred and it fails over to the other if the first goes down.
C) It randomly picks one for each packet.
D) It always uses the last added default route.

B — It uses the metric value; the route with the lower metric is preferred and it fails over to the other if the first goes down.

Why was Network Address Translation (NAT) invented and what primary problem does it solve?
A) To encrypt all internet traffic between home networks and ISPs.
B) To allow many devices using private IP addresses to access the internet via one legitimate public IP because IPv4 addresses were becoming scarce.
C) To replace routers with switches for better MAC address management.
D) To assign public IPs to every device automatically without a router.

B — To allow many devices using private IP addresses to access the internet via one legitimate public IP because IPv4 addresses were becoming scarce.

When a NAT-enabled router forwards an outgoing packet from an internal host to the internet, what does it typically do?
A) It forwards the packet unchanged and relies on the ISP to translate addresses.
B) It replaces the packet's source IP with the router's WAN (public) IP, records the original internal IP/port mapping in a table, and sends the packet out.
C) It broadcasts the packet to all hosts on the local network.
D) It changes the destination IP to the router's IP and drops the packet.

B — It replaces the packet's source IP with the router's WAN (public) IP, records the original internal IP/port mapping in a table, and sends the packet out.

What is a primary downside of NAT for hosting services on an internal device?
A) NAT causes all internal hosts to share the same MAC address.
B) NAT prevents internal hosts from initiating outbound connections.
C) NAT blocks unsolicited inbound connections unless you configure static NAT/port forwarding or the internal host initiates the conversation first.
D) NAT requires every internal device to have a public IP.

C — NAT blocks unsolicited inbound connections unless you configure static NAT/port forwarding or the internal host initiates the conversation first.

What is Static NAT (often called port forwarding)?
A) Assigning a random public IP from a pool to an internal host every time it connects.
B) Mapping a single public IP address permanently to a specific internal host so incoming traffic to that public IP always goes to that host.
C) Translating multiple internal IPs to one public IP using unique ports.
D) Automatically balancing outgoing connections across multiple ISPs.

B — Mapping a single public IP address permanently to a specific internal host so incoming traffic to that public IP always goes to that host.

What describes Dynamic NAT (pooled NAT) and its limitation?
A) It maps many private IPs to one public IP using different source ports with unlimited capacity.
B) It uses a pool of public IP addresses and assigns one temporarily to an internal host when it needs to access the internet; it’s limited because the number of simultaneous internal users cannot exceed the size of the public-IP pool.
C) It permanently assigns a public IP to every internal host regardless of use.
D) It encrypts traffic between two public IP addresses.

B — It uses a pool of public IP addresses and assigns one temporarily to an internal host when it needs to access the internet; it’s limited because the number of simultaneous internal users cannot exceed the size of the public-IP pool.

What is "regular NAT" or Port Address Translation (PAT) and how does it differ from static and dynamic NAT?
A) PAT maps one internal IP to one public IP permanently; it is the same as static NAT.
B) PAT maps multiple internal IP addresses to a single public IP by using different source ports, allowing many hosts to share one public IP; unlike static NAT it’s not a one-to-one mapping, and unlike dynamic NAT it uses port multiplexing rather than consuming multiple public IPs.
C) PAT assigns public IPs from a pool on a first-come-first-served basis and cannot use ports.
D) PAT requires a separate public IP per service and cannot be used for general web browsing.

B —

What is the default NAT configuration on most home routers?
A) NAT disabled
B) NAT enabled
C) NAT optional
D) NAT requires manual setup

B — NAT enabled

Why do enterprise-level routers usually not have NAT enabled by default?
A) Enterprises don’t use IP addresses
B) Enterprises rely on public IP blocks
C) NAT is too slow for enterprises
D) NAT is illegal in enterprise networks

B — Enterprises rely on public IP blocks

In the example, what WAN IP address did the ISP assign to the router?
A) 192.168.13.1
B) 161.16.5.13
C) 10.0.0.1
D) 172.16.5.13

B — 161.16.5.13

What IP address is used by the Linksys router on the LAN side?
A) 192.168.13.1
B) 161.16.5.13
C) 192.168.0.100
D) 10.0.0.1

A — 192.168.13.1

What range of IP addresses does the router’s DHCP server assign to clients?
A) 192.168.1.1 to 192.168.1.254
B) 192.168.13.1 to 192.168.13.50
C) 192.168.13.100 and up
D) 10.0.0.100 and up

C — 192.168.13.100 and up

What is one reason most users don’t need to manually configure IP addresses when setting up home internet?
A) NAT and DHCP handle addressing automatically
B) ISPs preconfigure all devices
C) Windows configures IPs by default
D) Routers don’t require IP addresses

A — NAT and DHCP handle addressing automatically

What does a SOHO firewall do with unsolicited inbound connections?
A) Allows them through
B) Blocks them unless initiated inside
C) Forwards them to the ISP
D) Converts them to HTTPS

B — Blocks them unless initiated inside

What is port forwarding (example: 1.1.1.1:8181 -> 192.168.5.13:80)?
A) Map a WAN IP:port to an internal host:port
B) Block all incoming traffic
C) Translate MAC addresses to IPs
D) Assign public IPs to internal hosts

A — Map a WAN IP:port to an internal host:port

What is port range forwarding used for?
A) Forward one port to many devices
B) Forward a contiguous range (e.g., 12001–12027) to one server
C) Encrypt a set of ports
D) Limit outgoing connections to a range

B — Forward a contiguous range (e.g., 12001–12027) to one server

How does port triggering (FTP) work?
A) Permanently opens ports for a host
B) Outbound on trigger port opens return ports temporarily
C) Permanently maps a public IP to an internal IP
D) Blocks FTP traffic entirely

B — Outbound on trigger port opens return ports temporarily

What is a SOHO DMZ and why is it risky?
A) A secure VPN service
B) Forwards all unsolicited inbound traffic to one host
C) A method to encrypt DMZ traffic
D) A cloud backup for router settings

B — Forwards all unsolicited inbound traffic to one host

Cloud vs local cameras: main security trade-off?
A) Cloud never stores video
B) Cloud phones home; local port-forwarding gives control
C) Cloud is always more secure
D) Local cameras cannot be accessed remotely

B — Cloud phones home; local port-forwarding gives control

What three pieces of information from the router documentation are most important for initial configuration?
A) Default IP address, default username, default password
B) IEEE warranty, cable type, installation media
C) Router weight, manufacturing date, OEM logo
D) Default DNS, default NTP server, default VLAN

A — Default IP address, default username, default password

After plugging a PC into a router LAN port, which command and output items help you confirm network settings?
A) Run ipconfig and check your assigned IP and default gateway
B) Run traceroute to check every hop to the internet
C) Use nslookup to list DHCP leases
D) Run netstat to view the router's firmware version

A — Run ipconfig and check your assigned IP and default gateway

Why might you change a router’s default LAN subnet from 192.168.1.0 to something unusual?
A) To reduce the chance attackers guess the internal network ID and improve security by obscurity
B) To make DHCP stop working on clients
C) To increase wireless signal strength
D) To force the router to use static WAN addressing

A — To reduce the chance attackers guess the internal network ID and improve security by obscurity

What is the purpose of MAC address cloning on some routers?
A) To mimic a PC’s MAC so a cable modem accepts the router after it was previously bound to the PC
B) To change the router’s LAN IP automatically
C) To encrypt traffic between the router and ISP
D) To speed up DHCP lease time

A — To mimic a PC’s MAC so a cable modem accepts the router after it was previously bound to the PC

Which administrative actions are recommended immediately after acquiring a home router?
A) Change the default admin username/password and disable remote web access unless needed
B) Enable remote web access on port 80 and leave default credentials
C) Remove firmware upgrade options to avoid updates
D) Set DHCP to assign public IPs to all clients

A — Change the default admin username/password and disable remote web access unless needed

What is the 30-30-30 hard-reset procedure and why is it used?
A) Hold reset 30s, unplug while holding 30s, plug while holding 30s; it restores factory defaults when configuration breaks
B) Press reset 3 times for 0.3s each to reboot the router quickly
C) Hold reset for 30s then release to factory-update firmware
D) Press reset and power buttons together for 30s to enable remote access

A — Hold reset 30s, unplug while holding 30s, plug while holding 30s; it restores factory defaults when configuration breaks

Which statement best describes a SOHO (small office/home office) gateway router?
A) A single device combining a router, switch, wireless AP, DHCP server, and firewall for small networks.
B) A rack-mounted metal box with modular interfaces and redundant power.
C) A device that never performs NAT or DHCP functions.
D) An enterprise-grade router designed for hundreds of hosts.

A — A single device combining a router, switch, wireless AP, DHCP server, and firewall for small networks.

Why do many SOHO routers appear to have multiple LAN ports?
A) Because they are two-port routers with a built-in switch so small networks don’t need a separate switch.
B) Because each port is a separate router module requiring its own license.
C) Because they provide redundant WAN uplinks by default.
D) Because each port only supports wireless clients.

A — Because they are two-port routers with a built-in switch so small networks don’t need a separate switch.

Which hardware features typically distinguish enterprise routers from SOHO routers?
A) Robust steel chassis, modular interface slots, higher throughput, and often redundant power supplies.
B) Built-in consumer Wi-Fi radios and simple web GUIs only.
C) Smaller memory and single USB-based configuration tools.
D) No support for dynamic routing protocols or VPNs.

A — Robust steel chassis, modular interface slots, higher throughput, and often redundant power supplies.

Which statement about enterprise routers and wireless/switching is correct?
A) Enterprise routers usually do not include wireless or built-in switching; those are provided by separate enterprise-grade APs and switches.
B) Enterprise routers always include integrated Wi-Fi and a 4-port consumer switch.
C) Enterprise routers cannot connect to external switches.
D) Enterprise routers are exclusively USB-powered devices for portability.

A — Enterprise routers usually do not include wireless or built-in switching; those are provided by separate enterprise-grade APs and switches.

What is a common method for configuring enterprise routers and what skill/knowledge is typically required?
A) Using a command-line interface (e.g., Cisco IOS via SSH/PuTTY) and learning vendor-specific commands (CCNA/CCNP are common certifications).
B) Only via a single-button web wizard with no need to learn commands.
C) By plugging a USB stick and auto-configuring with no credentials.
D) Using mobile apps only, with no CLI support.

A — Using a command-line interface (e.g., Cisco IOS via SSH/PuTTY) and learning vendor-specific commands (CCNA/CCNP are common certifications).

Which services and capabilities are more likely to be separately handled or more advanced on enterprise routers compared to SOHO devices?
A) Advanced dynamic routing protocols, high-capacity VPN termination, and separate, customizable firewall appliances.
B) Simple one-click port forwarding and default NAT only.
C) Consumer-grade parental controls and mobile app pairing exclusively.
D) Only DHCP, with no support for routing between networks.

A — Advanced dynamic routing protocols, high-capacity VPN termination, and separate, customizable firewall appliances.c

What is a static route?
A) A fixed route manually entered into a routing table that does not change automatically.
B) A route learned dynamically from other routers using a protocol like OSPF.
C) A temporary route created by NAT for outbound traffic.
D) A multicast route used for streaming.

A — A fixed route manually entered into a routing table that does not change automatically.

Which devices have routing tables on a TCP/IP network?
A) Only core routers in data centers
B) Every router and every host (computer) on a TCP/IP network
C) Only enterprise routers and managed switches
D) Only devices running BGP

B — Every router and every host (computer) on a TCP/IP network

Which command on Windows shows the routing table and is equivalent to netstat -r?
A) route print
B) ipconfig /renew
C) tracert
D) nslookup

A — route print

In a routing table, what does a destination of 0.0.0.0 with mask 0.0.0.0 usually indicate?
A) The default route — send packets here if no more specific route matches
B) A directly connected LAN subnet
C) The loopback interface
D) A multicast address range

A — The default route — send packets here if no more specific route matches

How is loopback traffic represented in routing tables and handled?
A) Addresses starting with 127.0.0.0/8 are routed "on-link" to the loopback and handled locally with no gateway.
B) Loopback uses 0.0.0.0 and always forwards to the default gateway.
C) Loopback addresses are in the 224.0.0.0 range for multicast routing.
D) Loopback requires a static route to an external router.

A — Addresses starting with 127.0.0.0/8 are routed "on-link" to the loopback and handled locally with no gateway.

When two routers are directly connected over a leased-line subnet (e.g., 17.18.19.0/24) so each LAN can reach the other, what must be configured?
A) Static routes on each router that point the remote LAN prefix to the leased-line next-hop IP on the other router
B) Change all hosts to public IPs from the ISP
C) Enable NAT on both routers only
D) Use multicast addresses for inter-LAN traffic

A — Static routes on each router that point the remote LAN prefix to the leased-line next-hop IP on the other router

What is network convergence?
A) When all routers have consistent routing information and traffic can be delivered after topology changes.
B) When a router's CPU reaches 100%.
C) When all hosts use the same subnet mask.
D) When NAT translates all addresses.

A — When all routers have consistent routing information and traffic can be delivered after topology changes.

Which metric refers to maximum transmission unit and affects fragmentation?
A) Hop count
B) MTU (maximum transmission unit)
C) Bandwidth
D) Latency

B — MTU (maximum transmission unit)

Which describes a distance-vector routing protocol?
A) Sends periodic full routing tables to neighbors and commonly uses hop count metrics.
B) Uses link-state advertisements and floods only changes.
C) Is used only between autonomous systems as an EGP.
D) Never updates routing tables automatically.

A — Sends periodic full routing tables to neighbors and commonly uses hop count metrics.

Which describes a link-state routing protocol?
A) Routers send hello/link-state advertisements about link changes and recompute routes locally for faster convergence.
B) Routers only use hop count and wait fixed intervals to update.
C) It is identical to static routing.
D) It cannot handle large networks.

A — Routers send hello/link-state advertisements about link changes and recompute routes locally for faster convergence.

What is an Autonomous System (AS) and which protocol is used between ASes?
A) An organization’s group of routers; BGP (Border Gateway Protocol) is the exterior gateway protocol used between ASes.
B) A LAN subnet; RIP is used between ASes.
C) A multicast group; OSPF is used between ASes.
D) A private IP pool; EIGRP is used between ASes.

A — An organization’s group of routers; BGP (Border Gateway Protocol) is the exterior gateway protocol used between ASes.

The metric in dynamic routing is used to select preferred paths. Which factors can metrics include?
A) Hop count, MTU, bandwidth, cost, and latency
B) Only hop count
C) Only physical cable color
D) Only MAC addresses

A — Hop count, MTU, bandwidth, cost, and latency

What type of protocol is OSPF?
A) Distance-vector
B) Link-state
C) Static
D) Hybrid

B — Link-state

Is OSPF an IGP or EGP?
A) IGP
B) EGP
C) Both
D) Neither

A — IGP

What does OSPF mainly use to calculate link costs?
A) Hop count
B) Bandwidth
C) Latency
D) MTU

B — Bandwidth

What is elected in an OSPF network segment to manage link-state advertisements?
A) Routing boss
B) Primary router
C) Designated Router (DR)
D) Control router

C — Designated Router (DR)

How are OSPF area IDs represented?
A) Look like MAC addresses
B) Look like IP addresses
C) Look like AS numbers
D) Look like hostnames

B — Look like IP addresses

Why is OSPF preferred over RIP?
A) Simpler configuration
B) Faster convergence
C) Lower memory use
D) Uses static routes

B — Faster convergence

What does BGP stand for?
A) Border Gateway Protocol
B) Basic Gateway Protocol
C) Broadband Global Protocol
D) Binary Gateway Process

A — Border Gateway Protocol

What is the main function of BGP?
A) Route within a LAN
B) Provide end-user IP addresses
C) Connect different autonomous systems
D) Encrypt traffic between routers

C — Connect different autonomous systems

What is an Autonomous System (AS)?
A) A private LAN
B) A group of IP networks under one admin
C) A single router
D) A security protocol

B — A group of IP networks under one admin

Which type of BGP runs inside an autonomous system?
A) eBGP
B) iBGP
C) OSPF
D) RIP

B — iBGP

Which type of BGP runs between different autonomous systems?
A) iBGP
B) eBGP
C) RIP
D) OSPF

B — eBGP

Why is BGP important for the internet?
A) It encrypts traffic
B) It ensures routing between ISPs
C) It assigns MAC addresses
D) It manages DNS servers

B — It ensures routing between ISPs

Which routing protocol was Cisco's first proprietary one?
A) OSPF
B) EIGRP
C) RIP
D) BGP

B — EIGRP

What type of protocol is EIGRP?
A) Distance-vector
B) Hybrid
C) Link-state
D) Static

B — Hybrid

Which older protocol did EIGRP replace for Cisco?
A) OSPF
B) RIP
C) IGRP
D) BGP

C — IGRP

What is EIGRP’s administrative distance (AD) value?
A) 90
B) 110
C) 120
D) 170

A — 90

Which multicast address does EIGRP use to send updates?
A) 224.0.0.10
B) 224.0.0.9
C) 224.0.0.5
D) 224.0.0.6

Which multicast address does EIGRP use to send updates?
A) 224.0.0.10
B) 224.0.0.9
C) 224.0.0.5
D) 224.0.0.6

What key feature makes EIGRP efficient?
A) Sends full updates always
B) Uses distance-vector only
C) Sends incremental updates
D) Requires manual updates

C — Sends incremental updates

Card 1
What does FHRP stand for?
A) Fast Host Routing Protocol
B) First Hop Redundancy Protocol
C) Fixed Hop Relay Protocol
D) Failover Host Recovery Protocol

B — First Hop Redundancy Protocol

What is the main purpose of FHRP?
A) To increase bandwidth
B) To provide redundancy for default gateways
C) To encrypt routing traffic
D) To create VLANs

B — To provide redundancy for default gateways

Which protocol is Cisco proprietary among FHRP options?
A) VRRP
B) HSRP
C) GLBP
D) OSPF

B — HSRP

Which FHRP allows load balancing across multiple routers?
A) HSRP
B) VRRP
C) GLBP
D) RIP

C — GLBP

Which FHRP is an open standard similar to HSRP?
A) EIGRP
B) VRRP
C) GLBP
D) BGP

B — VRRP

What happens when the active router in HSRP fails?
A) The whole network stops
B) The standby router takes over
C) A new VLAN is created
D) OSPF reroutes traffic

B — The standby router takes over