BGP auto-summary

If there’s auto-summary, a subnet that’s redistributed into BGP will be shown in the BGP table in its classful network form. Otherwise, it’ll be shown as it is in the routing table.
Recall that the router will choose a best route from the BGP table and will advertise it.

without auto-summary

with auto-summary:
Both subnets (off the routing table) will be summarized to 209.65.200.0/24, their classful network:

don’t forget to clear the session with neighbor after auto-summary:

network 209.65.200.224/30 is there because it is advertised with a network command. But 209.65.200.240/29 is summarized to its classful network 209.65.200.0/24

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