Hello, I have a system that detects attacks (DDOS) on the CCR and by BGP sends to my main router an IP address in the prefix / 32 which is being attacked.
How can I send such an IP address with a changed community to my upstreamers to cut the address? An example from BIRD:
So if it detects / 32 from community XXX, 666 changes it to 1234,666 and sends it to upstremers.

hello,
which system do you use for detect dddos ?

The question will rely on your upstream provider - so you will need to know what they expect so you can tag the route specifically. They will likely accept routes down to /32 with community <AS>:666 so they know to add as blackhole. Adjust your filters to look for routes with your own blackhole community and add the upstreams blackhole community on export.