JN0-102 · Question #317
Given the routing entries shown in the exhibit, which next-hop IP address will be used for the destination IP address 192.168.1.142? (Assume that only static routes are available for the destination.)
The correct answer is D. 10.20.14.130. For the destination 192.168.1.142, the router applies the longest prefix match rule, selecting the 192.168.1.128/28 static route as it is more specific than 192.168.1.128/27, leading to a next-hop of 10.20.14.130.
Question
Given the routing entries shown in the exhibit, which next-hop IP address will be used for the destination IP address 192.168.1.142? (Assume that only static routes are available for the destination.) user@router> show route protocol static inet.0: 12 destinations, 12 routes (12 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 192.168.1.128/27 *[Static/5] 00:03:13 > to 10.20.106.10 via fe-0/0/5.106 192.168.1.144/29 *[Static/5] 00:03:13 > to 10.20.14.131 via ge-0/0/0.0 192.168.1.192/27 *[Static/5] 00:03:13 > to 10.18.1.1 via ge-0/0/1.0 192.168.1.128/28 *[Static/5] 00:01:06 > to 10.20.14.130 via ge-0/0/0.0
Options
- A10.20.106.10
- B10.20.14.131
- C10.18.1.1
- D10.20.14.130
How the community answered
(31 responses)- A13% (4)
- B6% (2)
- C3% (1)
- D77% (24)
Why each option
For the destination 192.168.1.142, the router applies the longest prefix match rule, selecting the `192.168.1.128/28` static route as it is more specific than `192.168.1.128/27`, leading to a next-hop of `10.20.14.130`.
`10.20.106.10` is the next-hop for `192.168.1.128/27`, which is a valid match but less specific than `192.168.1.128/28`.
`10.20.14.131` is the next-hop for `192.168.1.144/29`, and `192.168.1.142` does not fall within this range.
`10.18.1.1` is the next-hop for `192.168.1.192/27`, and `192.168.1.142` does not fall within this range.
The destination IP address `192.168.1.142` falls within the ranges of `192.168.1.128/27` (128-159) and `192.168.1.128/28` (128-143). According to the longest prefix match rule, the most specific route is chosen. `192.168.1.128/28` is a longer (more specific) prefix than `192.168.1.128/27`, so its next-hop, `10.20.14.130`, will be used.
Concept tested: Longest prefix match routing
Source: https://www.juniper.net/documentation/us/en/software/junos/policy-routing/topics/topic-map-policy-routing-overview.html
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