FortiGate_A and FortiGate_B are in the same autonomous system (AS), and FortiGate_A does not currently have route 172.16.1.248/30 in its routing table. However, FortiGate_B has this route as a connected route.

To dynamically advertise only 172.16.1.248/30 from FortiGate_B to FortiGate_A, the administrator must configure a BGP route map out on FortiGate_B that specifically permits only this prefix.

A BGP route map out on FortiGate_B controls which routes FortiGate_B advertises to FortiGate_A. If no filtering is applied, FortiGate_B might advertise all BGP-learned and connected routes, which is not what the administrator wants. The route map should include a prefix-list that explicitly allows only 172.16.1.248/30 and denies everything else.