public static boolean internalIp(String ip) {     byte[] addr = IPAddressUtil.textToNumericFormatV4(ip);     return internalIp(addr); } public static boolean internalIp(byte[] addr) {     final byte b0 = addr[0];     final byte b1 = addr[1];     //10.x.x.x/8     final byte SECTION_1 = 0x0A;     //172.16.x.x/12     final byte SECTION_2 = (byte) 0xAC;     final byte SECTION_3 = (byte) 0x10;     final byte SECTION_4 = (byte) 0x1F;     //192.168.x.x/16     final byte SECTION_5 = (byte) 0xC0;     final byte SECTION_6 = (byte) 0xA8;     switch (b0) {         case SECTION_1:             return true;         case SECTION_2:             if (b1 >= SECTION_3 && b1 <= SECTION_4) {                 return true;             }         case SECTION_5:             switch (b1) {                 case SECTION_6:                     return true;             }         default:             return false;     } }