Question: OS: CentOS 6.4 (server)

I have successfully installed (yum install dsc20) the cassandra database layer in my server and can connect to it using the CQL SHel (cqlsh). But I need to run queries remotely using the DataStax's DevCenter software. So I installed it (DevCenter) in a separate workstation. (CentOS 6.4 - desktop) and tried to add a new connection in order to connect to the cassandra db.

So I gave the IP of the "CentOS 6.4 - server" (in which cassandra database is running) for the host and the port as 9160. But when testing the connection it fails.

I also tried to turn off the firewall in the server, (/etc/init.d/iptables stop). But was no luck.

I'm sure this may be due to some misconfiguration which I cannot figure out. I'll be grateful, if someone can give me a solution for this as I was researching for this and found no answers. Thank you very much in advance.

Answer: 
DataStax DevCenter being built on top of the DataStax Java driver has the same [connectivity requirements as the driver](https://github.com/datastax/java-driver/wiki/Connection-requirements). Namely:

1. `start_native_transport: true`
2. `rpc_address`: IP or hostname reachable from the client
3. Machines in the cluster accept connections on port `9042` (the `native_transport_port` config option)

If `rpc_address` is set to either a private IP or to `0.0.0.0`, DevCenter will not know what node to connect to. 

If your cluster has multiple nodes and these are using `rpc_address: 0.0.0.0`, even if you configure DevCenter with the IP(s) of a couple of nodes, it will still have issues discovering the other nodes in the cluster.

In [`cassandra.yaml`](https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L346) there's a comment/warning about using `rpc_address: 0.0.0.0`:

> 
> Note that unlike ListenAddress above, it is allowed to specify 0.0.0.0
>  here if you want to listen on all interfaces, but that will break clients 
>  that rely on node auto-discovery.
> 
> 
> 

*Note*: it is possible that in the future DevCenter might be able to ignore/filter out nodes in the cluster configured with `rpc_address: 0.0.0.0`.
If there's somebody working with docker locally, it can run this command.

```
docker run --name cassandra -p 127.0.0.1:9042:9042 -p 127.0.0.1:9160:9160 
-e CASSANDRA_LISTEN_ADDRESS=localhost 
-e CASSANDRA_BROADCAST_ADDRESS=localhost
-e CASSANDRA_RPC_ADDRESS=localhost -d cassandra

```