Unable to backup an R2 UNC-520 database, receive error java.net.ConnectException: Connection refused: connect at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(Unknown Source)...

Issue

Unable to backup an R2 UNC-520 database, receive error  "java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)           
at java.net.PlainSocketImpl.doConnect(Unknown Source)        
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)           
at java.net.PlainSocketImpl.connect(Unknown Source)           
at java.net.Socket.connect(Unknown Source)  
at java.net.Socket.connect(Unknown Source)  
at java.net.Socket.(Unknown Source)          
at java.net.Socket.(Unknown Source)      
at tridium.nre.drivers.SocketDriver$TcpSocketFactory.createSocket(SocketDriver.java:690)       
at tridium.nre.drivers.SocketDriver.create(SocketDriver.java:216)           
at tridium.nre.drivers.SocketDriver$ConnectThread.run(SocketDriver.java:510)"

Product Line

TAC I/A Series

Environment

I/A Series R2 UNC-520

I/A Series R2 WorkPlace Pro,  error reported in build r2.301.529

Cause

The WorkPlace Pro cannot connect to the UNC-520 at the given IP address. 

The error message stems from a bug in the Sun java, "The Socket constructor does not give an Exception on an unknown IP address. It just hangs."
 http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4232651

Resolution

Verify that the UNC is capable of communicating at the IP address specified. For example, if the UNC is rebooting constantly, it will not be able to communicate.