diff --git a/bin/debug.js b/bin/debug.js
new file mode 100644
index 0000000..f213e7e
--- /dev/null
+++ b/bin/debug.js
@@ -0,0 +1,54 @@
+(function () {
+'use strict';
+
+var input = process.argv[2];
+var fs = require('fs');
+var nb = fs.readFileSync(input, null);
+
+var ab = nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength)
+var dv = new DataView(ab);
+
+//
+// read header
+//
+console.log('');
+console.log('//////////////////');
+console.log('//    HEADER    //');
+console.log('//////////////////');
+console.log('');
+
+console.log('id (int)', dv.getUint16(0));
+
+var i = dv.getUint16(2, false);
+console.log('header 0x', i.toString(16));
+var flagsstr = ''
+	+ 'qr ' + ((i & 0x8000) >> 15) + ', '
+  + 'opcode ' + ((i & 0x7800) >> 11) + ', '
+  + 'aa ' + ((i &  0x400) >> 10) + ', '
+  + 'tc ' + ((i &  0x200) >>  9) + ', '
+  + 'rd ' + ((i &  0x100) >>  8) + ', '
+  + 'ra ' + ((i &   0x80) >>  7) + ', '
+  + 'res1 ' + ((i &   0x40) >>  6) + ', '
+  + 'res2 ' + ((i &   0x20) >>  5) + ', '
+  + 'res3 ' + ((i &   0x10) >>  4) + ', '
+  + 'rcode ' + ((i &    0xF));
+console.log('(flags: ' + flagsstr);
+
+var qdcount = dv.getUint16(4, false);  // query count
+var ancount = dv.getUint16(6, false);  // answer count
+var nscount = dv.getUint16(8, false);  // authority count
+var arcount = dv.getUint16(10, false); // additional count
+
+console.log('qdcount', qdcount);
+console.log('ancount', ancount);
+console.log('nscount', nscount);
+console.log('arcount', arcount);
+
+console.log('');
+console.log('//////////////////');
+console.log('//   QUESTION   //');
+console.log('//////////////////');
+console.log('');
+
+
+}());