Here you can find the source of isCommonSubnet(InetAddress address1, InetAddress address2)
public static boolean isCommonSubnet(InetAddress address1, InetAddress address2)
//package com.java2s; /**/*from w w w .j a v a2 s . c om*/ * * Copyright (C) 2004-2008 FhG Fokus * * This file is part of the FhG Fokus UPnP stack - an open source UPnP implementation * with some additional features * * You can redistribute the FhG Fokus UPnP stack and/or modify it * under the terms of the GNU General Public License Version 3 as published by * the Free Software Foundation. * * For a license to use the FhG Fokus UPnP stack software under conditions * other than those described here, or to purchase support for this * software, please contact Fraunhofer FOKUS by e-mail at the following * addresses: * upnpstack@fokus.fraunhofer.de * * The FhG Fokus UPnP stack is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see <http://www.gnu.org/licenses/> * or write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ import java.net.InetAddress; public class Main { /** Checks if two IP addresses belong to the same subnet */ public static boolean isCommonSubnet(InetAddress address1, InetAddress address2) { // check source of request message byte[] address1data = address1.getAddress(); byte[] address2data = address2.getAddress(); // check if request is from local network return address1data[0] == address2data[0] && address1data[1] == address2data[1] && address1data[2] == address2data[2]; } }