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Difficulty: Very hardIPv4 Static Routing

An enterprise router R1 learns the internal destination network 10.50.0.0/1610.50.0.0/16 dynamically via OSPF (default Administrative Distance of 110). A network administrator needs to manually configure two IPv4 static routes on R1:
1. A secondary backup (floating) static route to reach 10.50.0.0/1610.50.0.0/16 via the next-hop IP address 192.168.12.2192.168.12.2.
2. A default static route to forward all non-matching IPv4 traffic to the upstream ISP router at next-hop IP 203.0.113.1203.0.113.1.

Which TWO commands must be configured on router R1 to achieve these routing requirements? (Select TWO.)

  1. ip route 10.50.0.0 255.255.0.0 192.168.12.2 130Answer
  2. ip route 0.0.0.0 0.0.0.0 203.0.113.1Answer
  3. C
    ip route 10.50.0.0 255.255.0.0 192.168.12.2 90
  4. D
    ip route 0.0.0.0 255.255.255.255 203.0.113.1

Answer

The correct commands are 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 130' to establish a floating static route with an Administrative Distance higher than OSPF (110), and 'ip route 0.0.0.0 0.0.0.0 203.0.113.1' to establish a standard default static route using the prefix 0.0.0.0/0.
To create a floating static route, the Administrative Distance specified at the end of the 'ip route' command must be higher than that of the primary routing source. Since OSPF has an AD of 110, setting an AD of 130 guarantees the route will only be installed in the Routing Information Base (RIB) if the primary OSPF route disappears. Additionally, a default static route requires matching any IP address, configured with destination network 0.0.0.0 and subnet mask 0.0.0.0 pointing to the next-hop router address.

Step-by-Step Solution

1
Determine the primary route's Administrative Distance (AD) for network 10.50.0.0/16.
OSPF has a default AD of 110.
Floating static routes must have an AD strictly greater than the active dynamic protocol's AD to remain inactive until primary route failure.
2
Validate the floating static route syntax and AD parameter.
The command syntax 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 130' specifies an AD of 130, which is higher than 110.
AD 130 ensures the static route remains floating in backup mode until OSPF drops the path.
3
Formulate the default static route syntax for all unrouted traffic.
A default route uses destination prefix 0.0.0.0 and subnet mask 0.0.0.0 followed by the next-hop IP 203.0.113.1.
The prefix 0.0.0.0 0.0.0.0 matches any IPv4 address with a 0-bit prefix length.

Key Concept

Floating Static Routes and Default Static Route Syntax
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Topics

IPv4 Static Routing

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