@Schildmeijer is largely right, however port 7001 is still used when using TLS Encrypted Internode communication
So my complete list would be for current versions of Cassandra:
- 7199 - JMX (was 8080 pre Cassandra 0.8.xx)
- 7000 - Internode communication (not used if TLS enabled)
- 7001 - TLS Internode communication (used if TLS enabled)
- 9160 - Thrift client API
- 9042 - CQL native transport port