1. A network administrator configures a router by the command ip route 0.0.0.0 0.0.0.0 209.165.200.226. What is the purpose of this command?
- to forward all packets to the device with IP address 209.165.200.226
- to forward packets destined for the network 0.0.0.0 to the device with IP address 209.165.200.226
- to provide a route to forward packets for which there is no route in the routing table
- to add a dynamic route for the destination network 0.0.0.0 to the routing table
Explanation: The command ip route 0.0.0.0 0.0.0.0 <next hop> adds a default route to the routing table of a router. When the router receives a packet and does not have a specific route toward the destination, it forwards the packet to the next hop indicated in the default route. A route created with the ip route command is a static route, not a dynamic route.
2. Which type of static route that is configured on a router uses only the exit interface?
- fully specified static route
- directly connected static route
- recursive static route
- default static route
Explanation: When only the exit interface is used, the route is a directly connected static route. When the next-hop IP address is used, the route is a recursive static route. When both are used, it is a fully specified static route.
3. A network administrator uses the command ip route 172.18.0.0 255.255.0.0 S0/0/1 to configure a floating static route on a router. That route will function as a backup route to reach the EIGRP learned network 172.18.0.0/16. After this configuration, the EIGRP route is removed from the routing table even though EIGRP is still functioning properly. Why is the static route not functioning as intended?
- The network mask is incorrectly configured.
- The next hop neighbor IP address is not configured.
- The destination network is incorrectly configured.
- The administrative distance value is not high enough on the static route.
Explanation: A floating static route requires an administrative distance greater than that of the dynamic routing protocol in order to be used as a backup route. In this problem an administrative distance greater than 90 would have to be added to the static route: ip route 172.18.0.0 255.255.0.0 S0/0/1 100.
4. What type of static route is created when the next-hop IP address and exit interface are specified?
- recursive static route
- directly connected static route
- fully specified static route
- floating static route
Explanation: A fully specified static route has the next-hop IP address and exit interface specified. A recursive static route has only the next-hop IP address specified. A directly attached static route has only the router exit interface specified. A floating static route has a higher metric than the dynamic routes and serves as a backup route.
5. What is the correct syntax of a floating static route?
- ip route 209.165.200.228 255.255.255.248 serial 0/0/0
- ip route 209.165.200.228 255.255.255.248 10.0.0.1 120
- ip route 172.16.0.0 255.248.0.0 10.0.0.1
- ip route 0.0.0.0 0.0.0.0 serial 0/0/0
Explanation: Floating static routes are used as backup routes, often to routes learned from dynamic routing protocols. To be a floating static route, the configured route must have a higher administrative distance than the primary route. For example, if the primary route is learned through OSPF, then a floating static route that serves as a backup to the OSPF route must have an administrative distance greater than 110. The administrative distance on a floating static route is put at the end of the static route: ip route 209.165.200.228 255.255.255.248 10.0.0.1 120.
6. Which static route statement shows a recursive IPv6 static route?
- ipv6 route 0::/0 S0/0/0 254
- ipv6 route 0::/0 S0/0/0
- ipv6 route 2001:db8:cafe:1::/56 S0/0/0 2001:db8:1000:10::1
- ipv6 route 2001:db8:cafe:1::/56 2001:db8:1000:10::1
- ipv6 route 2001:db8:cafe:1::/56 S0/0/0
Explanation: In a recursive static route, only the next-hop IPv6 address is specified. As a consequence, the router must perform a recursive route table lookup to find an exit interface associated with the network of the IPv6 address.
7. A network administrator is configuring a route to forward packets to a specific web server. What type of route should be configured by the administrator?
- an OSPF route
- a static route with an administrative distance higher than 1
- a default route
- a host route
- an EIGRP route
Explanation: A host route is a route installed in the routing table where the destination address has a subnet mask of /32 for IPv4 or /128 for IPv6, an address of a specific device. A host route can allow for a more efficient processing of packets that are directed to the device, rather than for packet forwarding, such as by a default route, an OSPF route, or an EIGRP route.
8. Which command would create a valid IPv6 default route?
- ipv6 route 2001:db8:acad:1:/64 ::1
- ipv6 route ::/128 2001:db8:acad:1::1
- ipv6 route ::/o 2001:db8:acad:2::a
- ipv6 route ::/0 fe80::1
Explanation: The correct prefix and prefix length for a default route is ::/0, which matches any address. ::/128 matches only the specific address of all zeros. When creating a static route that uses a link-local address as the next hop, an exit interface must also be specified for the route to be valid.
9. What is a characteristic of a default static route?
- It backs up a route already discovered by a dynamic routing protocol.
- It is configured with a higher administrative distance than is the original dynamic routing protocol.
- It uses a single network address to send multiple static routes to one destination address.
- It identifies the gateway IP address to which the router sends all IP packets for which it does not have a learned or static route.
Explanation: A default static route is a route that matches all packets. It identifies the gateway IP address to which the router sends all IP packets for which the router does not have a learned or static route. A default static route is simply a static route with 0.0.0.0/0 as the destination IPv4 address. Configuring a default static route creates a gateway of last resort.
10. What is the purpose of a floating static route?
- It is commonly used when a dynamic routing protocol is not being used.
- It allows connectivity to remote destinations that are not contained in the routing table.
- It allows summarization of contiguous networks.
- It allows an alternate connection to be used when the preferred link fails.
Explanation: A floating static route is a backup route with an administrative distance that is higher than a dynamically learned route or another static route. The purpose of a floating static route is to use a particular path to a destination network that is not the best route, but is used only when the preferred route is down.
11. Which IPv6 static route would serve as a backup route to a dynamic route learned through OSPF?
- Router1(config)# ipv6 route 2001:db8:acad:1::/32 gigabitethernet0/0 2001:db8:acad:6::100 100
- Router1(config)# ipv6 route 2001:db8:acad:1::/32 2001:db8:acad:6::100
- Router1(config)# ipv6 route 2001:db8:acad:1::/32 2001:db8:acad:6::2 100
- Router1 (config)# ipv6 route 2001:db8:acad:1::/32 2001:db8:acad:6::2 200
Explanation: The command ipv6 route 2001:db8:acad:1::/32 2001:db8:acad:6::2 200, specifies a floating static route to the 2001:db8:acad:1::/32 network with an administrative distance of 200. Since OSPF has an administrative distance of 110, the static route would only be placed in the routing table if the OSPF learned route was removed.
12. What command, or set of commands, would be used to determine if the following configuration on router HQ works as designed?
ip route 0.0.0.0 0.0.0.0 serial 0/0/0 10 ip route 0.0.0.0 0.0.0.0 serial 0/1/0
- HQ# traceroute 128.107.0.99
- HQ# show ip route
- HQ(config)# interface serial 0/1/0
HQ(config-if)# shutdown
HQ(config-if)# end
HQ# show ip route - HQ# ping 128.107.0.99
HQ# ping 64.100.0.5 - HQ# show ip interface brief
Explanation: To test a floating static route, take down the main route/link in order to see whether the backup link appears in the routing table. The show ip route command simply shows the routing table. Only one of the static routes would be shown at any one time.
13. Which type of static route typically uses the distance parameter in the ip route global configuration command?
- floating static route
- summary static route
- standard static route
- default static route
Explanation: Because a floating static route is not designed to be used as a primary route, its configuration requires a higher administrative distance than the usual default value of 1. When set higher than the administrative distance for the current routing protocol, the distance parameter allows the route to be used only when the primary route fails. All other forms of static routes have specific uses as primary routes.
14. Why would a floating static route be configured with an administrative distance that is higher than the administrative distance of a dynamic routing protocol that is running on the same router?
- to be used as a backup route
- to load-balance the traffic
- to act as a gateway of last resort
- to be the priority route in the routing table
Explanation: By default, dynamic routing protocols have a higher administrative distance than static routes. Configuring a static route with a higher administrative distance than that of the dynamic routing protocol will result in the dynamic route being used instead of the static route. However, should the dynamically learned route fail, then the static route will be used as a backup.
15. What network address and subnet mask combination would be used to create a default static route that matches any IPv4 destination?
- 0.0.0.0 0.0.0.0
- 255.255.255.255 0.0.0.0
- 255.255.255.255 255.255.255.255
- 0.0.0.0 255.255.255.255
Explanation: For a route to be considered a default static route it must use a network ID and subnetmask combination that will match any destination IP address. The address and mask of 0.0.0.0 0.0.0.0 in a static route will create a route table entry that matches any destination.