You can access network parameters about a network interface beyond the name and IP addresses assigned to it

You can discover if a network interface is “up” (that is, running) with the isUP() method. The following methods indicate the network interface type:

• isLoopback() indicates if the network interface is a loopback interface.
• isPointToPoint() indicates if the interface is a point-to-point interface.
• isVirtual() indicates if the interface is a virtual interface.

The supportsMulticast() method indicates whether the network interface supports multicasting. The getHardwareAddress() method returns the network interface's physical hardware address, usually called MAC address, when it is available. The getMTU() method returns the Maximum Transmission Unit (MTU), which is the largest packet size.

The following example expands on the example in Listing Network Interface Addresses by adding the additional network parameters described on this page:

/*
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 * modification, are permitted provided that the following conditions
 * are met:
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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import java.io.*;
import java.net.*;
import java.util.*;
import static java.lang.System.out;

public class ListNetsEx
{
    public static void main(String args[]) throws SocketException {
        Enumeration<NetworkInterface> nets = NetworkInterface.getNetworkInterfaces();
        for (NetworkInterface netint : Collections.list(nets))
            displayInterfaceInformation(netint);
    }

    static void displayInterfaceInformation(NetworkInterface netint) throws SocketException {
        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");

     }
}  

The following is sample output from the example program:

Display name: bge0
Name: bge0
InetAddress: /fe80:0:0:0:203:baff:fef2:e99d%2
InetAddress: /129.156.225.59
Up? true
Loopback? false
PointToPoint? false
Supports multicast? false
Virtual? false
Hardware address: [0, 3, 4, 5, 6, 7]
MTU: 1500

Display name: lo0
Name: lo0
InetAddress: /0:0:0:0:0:0:0:1%1
InetAddress: /127.0.0.1
Up? true
Loopback? true
PointToPoint? false
Supports multicast? false
Virtual? false
Hardware address: null
MTU: 8232