A route reflector (RR) reflects an iBGP-learned prefix from client A to client B, but client B cannot reach the route's next-hop. Which configuration on the RR will ensure client B receives a reachable next-hop for reflected routes?

The correct answer is to configure 'next-hop-self' on the RR for reflected advertisements. By default, iBGP does not change the next-hop attribute when reflecting routes. If the next-hop of a reflected route is not directly connected or reachable within client B's IGP, client B will consider the route unreachable. 'next-hop-self' forces the RR to advertise itself as the next-hop for reflected routes, ensuring reachability for client B. Configuring AS path prepending on the RR is used for influencing outbound routing decisions by making a path appear longer, not for next-hop reachability. Enabling a route-map to set weight on the RR is a local preference metric used for inbound routing decisions and does not affect next-hop reachability. Converting the RR to an eBGP speaker would fundamentally change the network topology and routing behavior, and is not a solution for the next-hop reachability issue within an iBGP setup.