Let's take a sample scenario where the connection to TDV Server from any third party tool using server's hostname in connection string is successful.  But, while connecting to TDV Server from a third party tool using load balancer URL fails with below error message  :

Failed to finish connect: 'Connection refused: no further information'.[jdbc-1906503]

How to resolve "connection refused" error while connecting to TIBCO Data Virtualization Server using a load balancer URL?

All supported operating systems.

TDV server has no awareness of the Load Balancer, or how the Load Balancer is distributing requests across nodes. The server binds to a port, and then listens for incoming requests at that port.
 
TDV Server listens for HTTP requests at the base port (9400 by default).
 
From the perspective of the TDV server, the only requirement is that you configure your Load Balancer to do the following:
 
1) forward HTTP requests to port 9400/9402 (Non SSL and SSL).

2) forward JDBC/ODBC requests to port 9401/9403(Non SSL and SSL).
     
To make a successful connection to TDV Server we need to check on below two requirement :

1) There is no network/firewall issue from Third party tool to load balancer on base+9 ports.

2) There is no network/firewall issue from load balancer server to TDV Server on base+9 ports.

If any of the above two conditions fails, discuss with your IT/Network teams to resolve the connectivity issue.
         

A quick way to check the connectivity to a server on specific port is to use "Telnet" utility.