es select intf

NetworkUtils.java

/**
     * Returns the first non-loopback address on any interface on the current host.
     *
     * @param ip_version Constraint on IP version of address to be returned, 4 or 6
     */
    public static InetAddress getFirstNonLoopbackAddress(StackType ip_version) throws SocketException {
        InetAddress address = null;

        Enumeration intfs = NetworkInterface.getNetworkInterfaces();

        List<NetworkInterface> intfsList = Lists.newArrayList();
        while (intfs.hasMoreElements()) {
            intfsList.add((NetworkInterface) intfs.nextElement());
        }

        // order by index, assuming first ones are more interesting
        try {
            final Method getIndexMethod = NetworkInterface.class.getDeclaredMethod("getIndex");
            getIndexMethod.setAccessible(true);

            CollectionUtil.timSort(intfsList, new Comparator<NetworkInterface>() {
                @Override
                public int compare(NetworkInterface o1, NetworkInterface o2) {
                    try {
                        return ((Integer) getIndexMethod.invoke(o1)).intValue() - ((Integer) getIndexMethod.invoke(o2)).intValue();
                    } catch (Exception e) {
                        throw new ElasticSearchIllegalStateException("failed to fetch index of network interface");
                    }
                }
            });
        } catch (Exception e) {
            // ignore
        }

        for (NetworkInterface intf : intfsList) {
            try {
                if (!intf.isUp() || intf.isLoopback())
                    continue;
            } catch (Exception e) {
                // might happen when calling on a network interface that does not exists
                continue;
            }
            address = getFirstNonLoopbackAddress(intf, ip_version);
            if (address != null) {
                return address;
            }
        }

        return null;
    }