Index: peripherals/nic/w5100_internals.h
===================================================================
--- peripherals/nic/w5100_internals.h   (revision 4648)
+++ peripherals/nic/w5100_internals.h   (working copy)
@@ -29,6 +29,10 @@
 #ifndef FUSE_W5100_INTERNALS_H
 #define FUSE_W5100_INTERNALS_H

+#ifdef WIN32
+#include <signal.h>
+#endif             /* #ifdef WIN32 */
+
 typedef enum w5100_socket_mode {
   W5100_SOCKET_MODE_CLOSED = 0x00,
   W5100_SOCKET_MODE_TCP,
Index: peripherals/nic/w5100_socket.c
===================================================================
--- peripherals/nic/w5100_socket.c  (revision 4648)
+++ peripherals/nic/w5100_socket.c  (working copy)
@@ -34,9 +34,7 @@
 #include <unistd.h>

 #ifdef WIN32
-#include <winsock.h>
-#include <signal.h>
-typedef int socklen_t;
+#include <winsock2.h>
 #else
 #include <arpa/inet.h>
 #include <netinet/in.h>
@@ -181,7 +179,6 @@
     int protocol = tcp ? IPPROTO_TCP : IPPROTO_UDP;
     const char *description = tcp ? "TCP" : "UDP";
     int final_state = tcp ? W5100_SOCKET_STATE_INIT : W5100_SOCKET_STATE_UDP;
-    int one = 1;

     w5100_socket_clean( socket_obj );

@@ -195,12 +192,17 @@
       return;
     }

+#ifndef WIN32
+    int one = 1;
+
+    /* Windows warning: this could forcibly bind sockets already in use */
     if( setsockopt( socket_obj->fd, SOL_SOCKET, SO_REUSEADDR, &one,
       sizeof(one) ) == -1 ) {
       nic_w5100_error( UI_ERROR_ERROR,
         "w5100: failed to set SO_REUSEADDR on socket %d; errno %d: %s\n",
         socket_obj->id, compat_socket_get_error(), compat_socket_get_error() );
     }
+#endif

     socket_obj->state = final_state;

@@ -423,6 +425,7 @@
       if( w5100_socket_bind_port( self, socket ) ) {
         w5100_socket_release_lock( socket );
         socket->bind_count = 0;
+        return;
       }
       w5100_socket_release_lock( socket );
       compat_socket_selfpipe_wake( self->selfpipe );
@@ -617,7 +620,7 @@

   nic_w5100_debug( "w5100: accepted connection from %s:%d on socket %d\n", inet_ntoa(sa.sin_addr), ntohs(sa.sin_port), socket->id );

-  if( close( socket->fd ) == -1 )
+  if( compat_socket_close( socket->fd ) == -1 )
     nic_w5100_debug( "w5100: error attempting to close fd %d for socket %d\n", socket->fd, socket->id );

   socket->fd = new_fd;
Index: peripherals/nic/w5100.c
===================================================================
--- peripherals/nic/w5100.c (revision 4648)
+++ peripherals/nic/w5100.c (working copy)
@@ -28,19 +28,11 @@

 #include "config.h"

-#include <errno.h>
 #include <pthread.h>
 #include <string.h>
 #include <sys/types.h>
 #include <unistd.h>

-#ifdef WIN32
-#include <signal.h>
-#else
-#include <netinet/in.h>
-#include <sys/socket.h>
-#endif
-
 #include "fuse.h"
 #include "ui/ui.h"
 #include "w5100.h"
@@ -400,20 +392,7 @@
 {
   va_list ap;

-#ifdef WIN32
-  /* pause because contents of the audio buffer are played into a loop */
-  fuse_emulation_pause();
-#endif
-
   va_start( ap, format );
   nic_w5100_vdebug( format, ap );
   va_end( ap );
-
-  va_start( ap, format );
-  ui_verror( severity, format, ap );
-  va_end( ap );
-
-#ifdef WIN32
-  fuse_emulation_unpause();
-#endif
 }
Index: compat/win32/socket.c
===================================================================
--- compat/win32/socket.c   (revision 4648)
+++ compat/win32/socket.c   (working copy)
@@ -1,4 +1,4 @@
-/* file.c: Socket-related compatibility routines
+/* socket.c: Socket-related compatibility routines
    Copyright (c) 2011 Sergio Baldoví, Philip Kendall

    $Id$
@@ -25,8 +25,8 @@

 #include <config.h>

-#include <winsock.h>
-typedef int socklen_t;
+#include <winsock2.h>
+#include <ws2tcpip.h>

 #include "compat.h"
 #include "fuse.h"
@@ -37,9 +37,11 @@

 struct compat_socket_selfpipe_t {
   SOCKET self_socket;
-  int port;
+  libspectrum_word port;
 };

+int compat_socket_selfpipe_test( compat_socket_selfpipe_t *self );
+
 int
 compat_socket_close( compat_socket_t fd )
 {
@@ -129,7 +131,14 @@
     fuse_abort();
   }

-  self->port = sa.sin_port;
+  self->port = ntohs( sa.sin_port );
+
+  /* Test communications in order to detect blocking firewalls */
+  if( compat_socket_selfpipe_test( self ) == -1 ) {
+    ui_error( UI_ERROR_ERROR,
+              "w5100: failed to test internal communications" );
+    fuse_abort();
+  }

   return self;
 }
@@ -152,7 +161,7 @@
   memset( &sa, 0, sizeof(sa) );
   sa.sin_family = AF_INET;
   sa.sin_addr.s_addr = htonl( INADDR_LOOPBACK );
-  memcpy( &sa.sin_port, self->port, 2 );
+  sa.sin_port = htons( self->port );

   sendto( self->self_socket, NULL, 0, 0, (struct sockaddr*)&sa, sizeof(sa) );
 }
@@ -171,6 +180,32 @@
   } while( bytes_read != -1 );
 }

+int
+compat_socket_selfpipe_test( compat_socket_selfpipe_t *self )
+{
+  fd_set readfds;
+  int active;
+  struct timeval tv = { 1, 0 };
+
+  /* Send testing packet */
+  compat_socket_selfpipe_wake( self );
+
+  /* Safe reading from control socket */
+  FD_ZERO( &readfds );
+  FD_SET( self->self_socket, &readfds );
+  active = select( 0, &readfds, NULL, NULL, &tv );
+  if( active == 0 || active == compat_socket_invalid ) {
+    return -1;
+  }
+
+  /* Discard testing packet */
+  if( FD_ISSET( self->self_socket, &readfds ) ) {
+    compat_socket_selfpipe_discard_data( self );
+  }
+
+  return 0;
+}
+
 void
 compat_socket_networking_init( void )
 {
Index: compat/unix/socket.c
===================================================================
--- compat/unix/socket.c    (revision 4648)
+++ compat/unix/socket.c    (working copy)
@@ -1,4 +1,4 @@
-/* file.c: Socket-related compatibility routines
+/* socket.c: Socket-related compatibility routines
    Copyright (c) 2011 Philip Kendall

    $Id$
(c) 2011 Philip Kendall

    $Id$