Get Local Host LAN Address

/**
* This method is intended for Linux Systems, as Linux fails to provide the external IP
* when using InetAddress.getLocalHost(). It instead provides the loopback address.
*
* @return
* @throws UnknownHostException
*/
private static InetAddress getLocalHostLANAddress() throws UnknownHostException {
try {
InetAddress candidateAddress = null;
// Iterate all NICs (network interface cards)...
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) {

NetworkInterface iface = ifaces.nextElement();
// Iterate all IP addresses assigned to each card...
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) {

InetAddress inetAddr = inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {

if (inetAddr.isSiteLocalAddress()) {
// Found non-loopback site-local address. Return it immediately...
return inetAddr;
}
else if (candidateAddress == null) {
// Found non-loopback address, but not necessarily site-local.
// Store it as a candidate to be returned if site-local address is not subsequently found...
candidateAddress = inetAddr;
// Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
// only the first. For subsequent iterations, candidate will be non-null.
}
}
}
}
if (candidateAddress != null) {
// We did not find a site-local address, but we found some other non-loopback address.
// Server might have a non-site-local address assigned to its NIC (or it might be running
// IPv6 which deprecates the "site-local" concept).
// Return this non-loopback candidate address...
return candidateAddress;
}
// At this point, we did not find a non-loopback address.
// Fall back to returning whatever InetAddress.getLocalHost() returns...
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
if (jdkSuppliedAddress == null) {
throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
}
return jdkSuppliedAddress;
}
catch (Exception e) {
UnknownHostException unknownHostException = new UnknownHostException("Failed to determine LAN address: " + e);
unknownHostException.initCause(e);
throw unknownHostException;
}
}