How to Configure a Route Map for Redistribution in BGP
Question
An engineer is implementing a route map to support redistribution within BGP.
The route map must be configured to permit all unmatched routes.
Which action must the engineer perform to complete this task?
Answers
Explanations
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A. B. C. D.D.
To understand the answer to this question, it's essential to know how route maps work and how they're used in BGP.
A route map is a policy tool that allows network administrators to filter and manipulate routes within a routing protocol. In BGP, route maps are commonly used to filter routes as they're redistributed between different routing protocols, or as they're advertised to BGP peers.
A route map consists of a sequence of match and set statements. The match statements define the criteria for selecting the routes that will be affected by the route map, while the set statements define the actions that will be taken on the selected routes.
By default, a route map has an implicit deny statement at the end of the sequence. This means that any routes that don't match any of the match statements will be denied by default. To permit all unmatched routes, the engineer must take one of the following actions:
A. Include a permit statement as the first entry. This is the correct answer. By including a permit statement as the first entry in the route map, the engineer ensures that any route that doesn't match any subsequent match statements will be permitted.
B. Remove the implicit deny entry. This would permit all routes, matched or unmatched, which may not be the desired behavior. It's better to keep the implicit deny and add a permit statement as the first entry.
C. Include at least one explicit deny statement. This would deny all routes that don't match any subsequent match statements, which is the opposite of what the question is asking for.
D. Include a permit statement as the last entry. This would permit all routes that don't match any previous match statements but would also permit any routes that do match previous match statements, which may not be the desired behavior. It's better to include the permit statement as the first entry.
In conclusion, to permit all unmatched routes in a BGP redistribution route map, an engineer should include a permit statement as the first entry in the sequence.
