net.corda.client.rpc.RPCException: Cannot connect to server(s). Tried with all available servers - corda

Question

OS: Windows 10 and Ubuntu 18.04
Corda: 4.4
I wanted to learn CordaRPCOps so I started by using the template’s Cordform deployNodes task that provides me with three running nodes.
First I used the following code running locally to connect to PartyA’s Corda node.
NetworkHostAndPort nodeAddress = new NetworkHostAndPort("localhost", 10006);
CordaRPCClient client = new CordaRPCClient(nodeAddress);
CordaRPCConnection connection = client.start("user1", "test");
CordaRPCOps cordaRPCOps = connection.getProxy();
This worked great.
Then I tried connecting from a different PC on the same network with the following change:
NetworkHostAndPort nodeAddress = new NetworkHostAndPort("192.168.1.149", 10006);
This failed with the following error:
net.corda.client.rpc.RPCException: Cannot connect to server(s). Tried with all available servers.
 
Assuming this was network related I went back to the local PC and ran the same code:
NetworkHostAndPort nodeAddress = new NetworkHostAndPort("192.168.1.149", 10006);
This also failed. So I decided to try the PC name instead of the IP address. This failed both locally and on the other PC.

Answer 1

If the rpcSettings in the node.conf file use “localhost”:
rpcSettings {
address="localhost:10006"
adminAddress="localhost:10046"
}
…you cannot connect to the node using anything but “localhost” or “127.0.0.1”
NetworkHostAndPort nodeAddress = new NetworkHostAndPort("localhost", 10006);
This also means you cannot connect to the node from across the network.
If you replace “localhost” with the IP address or the computer name:
rpcSettings {
address="192.168.1.149:10006"
adminAddress="localhost:10046"
}
… then you can reference the node by either IP or computer name locally, or from another PC on the network:
NetworkHostAndPort nodeAddress = new NetworkHostAndPort("192.168.1.149", 10006);
You’ll notice the change on the opening screen of the Node Shell when they start and list their respective information.
--- Corda Open Source 4.4 (21e8c4f) -------------------------------------------------------------
Logs can be found in : F:\corda\Java\cordapp-template-java\build\nodes\PartyA\logs
! ATTENTION: This node is running in development mode! This is not safe for production deployment.
Jolokia: Agent started with URL http://127.0.0.1:7006/jolokia/
Advertised P2P messaging addresses : localhost:10005
RPC connection address : 192.168.1.149:10006
RPC admin connection address : localhost:10046