Can anyone explain why Java GetNetworkInterfaces returns so many interfaces on Windows 7

I have been using NetworkInterface.getNetworkInterfaces() to query the Network Interfaces on my machine. Essentially I am trying to find Network Interface Cards. These are usually called something like eth0, eth1 etc..

Its been working great on win xp and even vista with a litle filtering.

I just noticed in certain configurations of windows 7 I get a large number of listed network adapters. Way more than on xp and vista. I have only one card configured but seem to get three different network interfaces

• Intel(R) 82567LM-3 Gigabit Network Connection
• Intel(R) 82567LM-3 Gigabit Network Connection-QoS Packet Scheduler-0000
• Intel(R) 82567LM-3 Gigabit Network Connection-WFP LightWeight Filter-0000

Why 3 different points for essentially the same thing.

I also have six entries for something called WAN MINIPORT. (See below for output)

I can filter out these but of course there is a performance cost in going through so much crap. Does anyone know why these entries are created and how to minimise them ?

As an example on my system I wrote code like this

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;

import static java.lang.System.out;


public class ListNetsEx {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Enumeration<NetworkInterface> nets;
        try {
            nets = NetworkInterface.getNetworkInterfaces();
            for (NetworkInterface netint : Collections.list(nets))
                displayInterfaceInformation(netint);
        } catch (SocketException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    private static void displayInterfaceInformation(NetworkInterface netint) throws SocketException {
        // TODO Auto-generated method stub
        out.printf("Display name: %s\n", netint.getDisplayName());
        out.printf("Name: %s\n", netint.getName());
        Enumeration<InetAddress> inetAddresses = netint.getInetAddresses();

        for (InetAddress inetAddress : Collections.list(inetAddresses)) {
            out.printf("InetAddress: %s\n", inetAddress);
        }

        out.printf("Up? %s\n", netint.isUp());
        out.printf("Loopback? %s\n", netint.isLoopback());
        out.printf("PointToPoint? %s\n", netint.isPointToPoint());
        out.printf("Supports multicast? %s\n", netint.supportsMulticast());
        out.printf("Virtual? %s\n", netint.isVirtual());
        out.printf("Hardware address: %s\n",
                    Arrays.toString(netint.getHardwareAddress()));
        out.printf("MTU: %s\n", netint.getMTU());

        out.printf("\n");

    }

}

On windows 7 output is

Display name: Software Loopback Interface 1
Name: lo
InetAddress: /0:0:0:0:0:0:0:1
InetAddress: /127.0.0.1
Up? true
Loopback? true
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: []
MTU: -1

Display name: WAN Miniport (SSTP)
Name: net0
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (IKEv2)
Name: net1
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (L2TP)
Name: net2
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (PPTP)
Name: net3
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (PPPOE)
Name: ppp0
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (IPv6)
Name: eth0
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: nu开发者_Go百科ll
MTU: -1

Display name: WAN Miniport (Network Monitor)
Name: eth1
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (IP)
Name: eth2
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: RAS Async Adapter
Name: ppp1
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: Intel(R) 82567LM-3 Gigabit Network Connection
Name: eth3
InetAddress: /fe80:0:0:0:b1b1:7531:17b1:bf26%11
InetAddress: /172.24.9.148
Up? true
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: [120, 43, -53, 125, -80, 74]
MTU: 1500

Display name: Microsoft ISATAP Adapter
Name: net4
Up? false
Loopback? false
PointToPoint? true
Supports multicast? false
Virtual? false
Hardware address: [0, 0, 0, 0, 0, 0, 0, -32]
MTU: 1280

Display name: Teredo Tunneling Pseudo-Interface
Name: net5
InetAddress: /fe80:0:0:0:e0:0:0:0%13
Up? false
Loopback? false
PointToPoint? true
Supports multicast? false
Virtual? false
Hardware address: [0, 0, 0, 0, 0, 0, 0, -32]
MTU: 1280

Display name: Microsoft ISATAP Adapter #2
Name: net6
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: Intel(R) 82567LM-3 Gigabit Network Connection-QoS Packet Scheduler-0000
Name: eth4
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: Intel(R) 82567LM-3 Gigabit Network Connection-WFP LightWeight Filter-0000
Name: eth5
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (Network Monitor)-QoS Packet Scheduler-0000
Name: eth6
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (IP)-QoS Packet Scheduler-0000
Name: eth7
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

Display name: WAN Miniport (IPv6)-QoS Packet Scheduler-0000
Name: eth8
Up? false
Loopback? false
PointToPoint? false
Supports multicast? true
Virtual? false
Hardware address: null
MTU: -1

---

Windows defines many interfaces for internal use. Java just returns what the OS tell gives it, none of these are added by Java.

You should be able to find entries for all these devices in the Windows Registry.