Cassandra cluster extension with one additional node: which ports should be open?

Question

Assume a Cassandra cluster with hosts A and B This cluster will now be expanded by another C host. Assuming C is on a firewall, all packets are discarded by default.

What ports and protocols should be open between C <> A and C <> B for the new node C function to work properly?

Answer 1

7000 TCP (internal communication port) Btw, see this question