Index: osscan2.cc
===================================================================
--- osscan2.cc	(revision 11131)
+++ osscan2.cc	(working copy)
@@ -931,6 +931,9 @@
     ethptr = ð
   } else {
     /* Init our raw socket */
+#ifdef WIN32
+    win32_warn_raw_sockets(t->deviceName());
+#endif
     if ((rawsd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0 )
       pfatal("socket troubles in %s", __func__);
     unblock_socket(rawsd);
Index: output.h
===================================================================
--- output.h	(revision 11131)
+++ output.h	(working copy)
@@ -125,6 +125,12 @@
 #include "nmap.h"
 #include "global_structures.h"
 
+#ifdef WIN32
+/* Display a warning that a device is not Ethernet and so raw sockets
+   will be used. The warning is shown only once per unique device name. */
+void win32_warn_raw_sockets(const char *devname);
+#endif
+
 /* Prints the familiar Nmap tabular output showing the "interesting"
    ports found on the machine.  It also handles the Machine/Greppable
    output and the XML output.  It is pretty ugly -- in particular I
Index: idle_scan.cc
===================================================================
--- idle_scan.cc	(revision 11131)
+++ idle_scan.cc	(working copy)
@@ -391,6 +391,9 @@
     proxy->rawsd = -1;
     proxy->ethptr = &proxy->eth;
   } else {
+#ifdef WIN32
+    win32_warn_raw_sockets(proxy->host.deviceName());
+#endif
     if ((proxy->rawsd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0 )
       pfatal("socket troubles in %s", __func__);
     unblock_socket(proxy->rawsd);
Index: output.cc
===================================================================
--- output.cc	(revision 11131)
+++ output.cc	(working copy)
@@ -114,6 +114,7 @@
 #include "Target.h"
 #include "utils.h"
 
+#include <set>
 #include <string>
 #include <vector>
 #include <list>
@@ -294,6 +295,17 @@
 }
 
 #ifdef WIN32
+/* Display a warning that a device is not Ethernet and so raw sockets
+   will be used. The warning is shown only once per unique device name. */
+void win32_warn_raw_sockets(const char *devname) {
+  static set<string> shown_names;
+
+  if (shown_names.find(devname) == shown_names.end()) {
+    error("WARNING: Using raw sockets because %s is not an ethernet device. This probably won't work on Windows.\n", devname);
+    shown_names.insert(devname);
+  }
+}
+
 /* From tcpip.cc. */
 bool DnetName2PcapName(const char *dnetdev, char *pcapdev, int pcapdevlen);
 
Index: scan_engine.cc
===================================================================
--- scan_engine.cc	(revision 11131)
+++ scan_engine.cc	(working copy)
@@ -1525,6 +1525,9 @@
       rawsd = -1;
     } else {
       /* Initialize a raw socket */
+#ifdef WIN32
+      win32_warn_raw_sockets(Targets[0]->deviceName());
+#endif
       if ((rawsd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0 )
 	pfatal("socket troubles in %s", __func__);
       /* We do not wan't to unblock the socket since we want to wait 
Index: traceroute.cc
===================================================================
--- traceroute.cc	(revision 11131)
+++ traceroute.cc	(working copy)
@@ -216,6 +216,9 @@
         if (ethsd == NULL)
             fatal ("dnet: Failed to open device %s", device_name);
     } else {
+#ifdef WIN32
+        win32_warn_raw_sockets(device_name);
+#endif
         if ((fd = socket (AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
             pfatal ("Traceroute: socket troubles");
         broadcast_socket (fd);