How to choose NIC that connect to Internet

Question

Hello,
I am developing VoIP application using Jain-SIP. it works nice in WinXP but when I try it on Ubuntu i got an exception :
"javax.Sip.SipException InvalidArgumentException"
after searching it on google, it tells that ubuntu return "127.0.1.1" when I execute InetAddress.getLocalhost().getHostAddress();
it was lead me to a forum that told a way how to get all interfaces physical and logical address, here is the code :
   for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {
                iface = (NetworkInterface) ifaces.nextElement();
                System.out.println("Interface :"+ iface.getDisplayName() );
            InetAddress ia = null;
            for(Enumeration ips = iface.getInetAddresses();ips.hasMoreElements();)
                ia = (InetAddress)ips.nextElement();
                System.out.println(ia.getCanonicalHostName()+":"+ia.getHostAddress());
            }it works beautifully. but....
my problem is, if one computer has 2 NIC, let say 1 Wireless connection and 1 ethernet connection, how can i choose one of those connection that connected to the internet ?
thanks.

Answer 1

banderaz wrote:
in case when an application start to run, or being installed, we need to configure "hosts" file in etc directory which need a super user priveleged, how can we do that ? Your app cannot solve all possible problems. At some point you must require that a system has certain things and make no guarantees if the system doesn't have it. One path you could take is to add a step to your installation instructions and require that the user verifies that the setup is correct.