Hello everyone, thank you for reading. I want to share my mistake so beginner can learn.
I rent 3$ VPS from CloudCone for learning BGP. They have looking glass and friendly support, thank you CloudCone team. I get /24 from my RIR, set up Bird2, announce to upstream.
Session come up, I see my prefix in their table, very happy. Then I check website, cannot reach. Then SSH disconnect. Then management IP no response.
47 seconds total. Wkwkwk
I think my prefix wrong, or upstream filter. No. I filter my own /32 management IP in Bird2 export filter. Prefix list deny my source, so return traffic drop. Thank you to support team for rescue console, very patient.
Lesson: never use IP inside announced block for management. Or if must, add explicit permit before deny. Thank you.