In certain situations, Mule ESB is not able to connect to a server. The problem can be caused by the IPv6 protocol.
java.net.SocketException: Network is unreachable: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.Socket.connect(Socket.java:518)
at java.net.Socket.connect(Socket.java:468)
The failure can be caused by the preference of IPv6. The JVM parameter force to use IPv4.
-Djava.net.preferIPv4Stack=true