IP Static Routing Chapter 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

• 0.0.0.0 255.255.255.255

• 255.255.255.255 0.0.0.0

• 255.255.255.255 255.255.255.255

Answer 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.

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 be the priority route in the routing table

• to act as a gateway of last resort

• to load-balance the traffic

Answer 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.

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

Answer 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.

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.

Answer 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.

What is a characteristic of a default static route? ​

• 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.

• It is configured with a higher administrative distance than is the original dynamic routing protocol.

• It backs up a route already discovered by a dynamic routing protocol.

• It uses a single network address to send multiple static routes to one destination address.

Answer 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.​

Which command would create a valid IPv6 default route?

• ipv6 route 2001:db8:acad:1::/64 ::1

• ipv6 route ::/0 fe80::1

• ipv6 route ::/0 2001:db8:acad:2::a

• ipv6 route ::/128 2001:db8:acad:1::1

Answer 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.

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?

• a default route

• an OSPF route

• an EIGRP route

• a static route with an administrative distance higher than 1

• a host route

Answer 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.

What is the correct syntax of a floating static route?

• ip route 172.16.0.0 255.248.0.0 10.0.0.1

• ip route 209.165.200.228 255.255.255.248 10.0.0.1 120

• ip route 0.0.0.0 0.0.0.0 serial 0/0/0

• ip route 209.165.200.228 255.255.255.248 serial 0/0/0

Answer 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.

What type of static route is created when the next-hop IP address and exit interface are specified?

• fully specified static route

• recursive static route

• directly connected static route

• Floating static route

Answer 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.

Which type of static route that is configured on a router uses only the exit interface?

• directly connected static route

• fully specified static route

• default static route

• recursive static route

Answer 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.