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Difficulty: MediumIPv4 Static Routing

An administrator needs to configure a backup static route on router R1 to reach destination network 10.20.30.0/2410.20.30.0/24 only if the primary path learned via internal EIGRP (Administrative Distance 9090) becomes unavailable. The next-hop IPv4 address for the backup path is 192.168.1.2192.168.1.2. Which command must be entered on router R1 to achieve this objective?

  1. ip route 10.20.30.0 255.255.255.0 192.168.1.2 95Answer
  2. B
    ip route 10.20.30.0 255.255.255.0 192.168.1.2 85
  3. C
    ip route 10.20.30.0 0.0.0.255 192.168.1.2 95
  4. D
    ip route 192.168.1.2 255.255.255.0 10.20.30.0 95

Answer

The command 'ip route 10.20.30.0 255.255.255.0 192.168.1.2 95' correctly configures a floating static route with an Administrative Distance higher than EIGRP.
The command specifying destination network 10.20.30.0, subnet mask 255.255.255.0, next-hop IP 192.168.1.2, and Administrative Distance 95 correctly establishes a floating static route. Because the AD of 95 is higher than Internal EIGRP's AD of 90, the router will use EIGRP during normal operations and only insert this static route into the routing table if the EIGRP path goes down.

Step-by-Step Solution

1
Identify the standard Cisco IOS IPv4 static route syntax.
Syntax: 'ip route <destination-network> <subnet-mask> <next-hop-ip> [administrative-distance]'
Correct command structure is required for syntax validity on Cisco routers.
2
Determine the required Administrative Distance (AD) for a floating static backup route.
AD must be greater than the primary route protocol's AD (90 for Internal EIGRP). Thus, AD = 95.
Routes with lower AD are preferred in the IP routing table. Setting AD higher than 90 ensures the static route remains inactive until EIGRP fails.
3
Combine the network parameters into the final command.
ip route 10.20.30.0 255.255.255.0 192.168.1.2 95
Matches destination 10.20.30.0/2410.20.30.0/24, next-hop 192.168.1.2192.168.1.2, and floating AD 95.

Key Concept

Floating Static Routes and Administrative Distance
Estimated Time:1m 15s
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Topics

IPv4 Static Routing

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