We have a problem joining new (old-dropped) node into Cassandra (Apache) Cluster.
The version is 3.11.2 - vnodes 128
It seems that during the bootstrap the streams start to flow ok.
At the end / after some time "Stream Failed".
One ERROR we have gotten is like
ERROR [Native-Transport-Requests-1] 2021-01-25 14:54:21,621 Message.java:629 - Unexpected exception during request; channel = [id: 0xf5c8dc6c, L:/10.51.105.67:9142 - R:/172.17.0.10:55246] java.lang.NullPointerException: null
..67 is the node in question, the 172 is docker address of a sending node"
We do suspect network failures. But how to prove "the NW is not valid"?
OR what kind of traces to run?