diff --git a/ares/nameser.h b/ares/nameser.h
index a7587d002..ec5e77aa0 100644
--- a/ares/nameser.h
+++ b/ares/nameser.h
@@ -18,11 +18,6 @@
 
 #define MAXHOSTNAMELEN 256
 
-#define EINPROGRESS WSAEINPROGRESS
-#define EWOULDBLOCK WSAEWOULDBLOCK
-#define EMSGSIZE     WSAEMSGSIZE
-#define EAFNOSUPPORT WSAEAFNOSUPPORT
-
 /* Structure for scatter/gather I/O.  */
 struct iovec
 {
diff --git a/ares/setup_once.h b/ares/setup_once.h
index 25eacf51e..6daf9d8b7 100644
--- a/ares/setup_once.h
+++ b/ares/setup_once.h
@@ -186,5 +186,50 @@ typedef int sig_atomic_t;
 #endif
 
 
+/*
+ * Portable error number symbolic names defined to Winsock error codes.
+ */
+
+#ifdef USE_WINSOCK
+#define EWOULDBLOCK      WSAEWOULDBLOCK
+#define EINPROGRESS      WSAEINPROGRESS
+#define EALREADY         WSAEALREADY
+#define ENOTSOCK         WSAENOTSOCK
+#define EDESTADDRREQ     WSAEDESTADDRREQ
+#define EMSGSIZE         WSAEMSGSIZE
+#define EPROTOTYPE       WSAEPROTOTYPE
+#define ENOPROTOOPT      WSAENOPROTOOPT
+#define EPROTONOSUPPORT  WSAEPROTONOSUPPORT
+#define ESOCKTNOSUPPORT  WSAESOCKTNOSUPPORT
+#define EOPNOTSUPP       WSAEOPNOTSUPP
+#define EPFNOSUPPORT     WSAEPFNOSUPPORT
+#define EAFNOSUPPORT     WSAEAFNOSUPPORT
+#define EADDRINUSE       WSAEADDRINUSE
+#define EADDRNOTAVAIL    WSAEADDRNOTAVAIL
+#define ENETDOWN         WSAENETDOWN
+#define ENETUNREACH      WSAENETUNREACH
+#define ENETRESET        WSAENETRESET
+#define ECONNABORTED     WSAECONNABORTED
+#define ECONNRESET       WSAECONNRESET
+#define ENOBUFS          WSAENOBUFS
+#define EISCONN          WSAEISCONN
+#define ENOTCONN         WSAENOTCONN
+#define ESHUTDOWN        WSAESHUTDOWN
+#define ETOOMANYREFS     WSAETOOMANYREFS
+#define ETIMEDOUT        WSAETIMEDOUT
+#define ECONNREFUSED     WSAECONNREFUSED
+#define ELOOP            WSAELOOP
+#define ENAMETOOLONG     WSAENAMETOOLONG
+#define EHOSTDOWN        WSAEHOSTDOWN
+#define EHOSTUNREACH     WSAEHOSTUNREACH
+#define ENOTEMPTY        WSAENOTEMPTY
+#define EPROCLIM         WSAEPROCLIM
+#define EUSERS           WSAEUSERS
+#define EDQUOT           WSAEDQUOT
+#define ESTALE           WSAESTALE
+#define EREMOTE          WSAEREMOTE
+#endif
+
+
 #endif /* __SETUP_ONCE_H */
 
diff --git a/lib/connect.c b/lib/connect.c
index 464b59098..5be0df27e 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -84,14 +84,6 @@
 #define FALSE 0
 #endif
 
-#ifdef USE_WINSOCK
-#define EINPROGRESS WSAEINPROGRESS
-#define EWOULDBLOCK WSAEWOULDBLOCK
-#define EISCONN     WSAEISCONN
-#define ENOTSOCK    WSAENOTSOCK
-#define ECONNREFUSED WSAECONNREFUSED
-#endif
-
 #include "urldata.h"
 #include "sendf.h"
 #include "if2ip.h"
diff --git a/lib/inet_ntop.c b/lib/inet_ntop.c
index f41a3f268..a0b8ba46b 100644
--- a/lib/inet_ntop.c
+++ b/lib/inet_ntop.c
@@ -55,10 +55,6 @@
 #define INADDRSZ         4
 #define INT16SZ          2
 
-#ifdef USE_WINSOCK
-#define EAFNOSUPPORT    WSAEAFNOSUPPORT
-#endif
-
 /*
  * Format an IPv4 address, more or less like inet_ntoa().
  *
diff --git a/lib/setup_once.h b/lib/setup_once.h
index 38d86db6f..630cd05e3 100644
--- a/lib/setup_once.h
+++ b/lib/setup_once.h
@@ -193,5 +193,50 @@ typedef int sig_atomic_t;
 #endif
 
 
+/*
+ * Portable error number symbolic names defined to Winsock error codes.
+ */
+
+#ifdef USE_WINSOCK
+#define EWOULDBLOCK      WSAEWOULDBLOCK
+#define EINPROGRESS      WSAEINPROGRESS
+#define EALREADY         WSAEALREADY
+#define ENOTSOCK         WSAENOTSOCK
+#define EDESTADDRREQ     WSAEDESTADDRREQ
+#define EMSGSIZE         WSAEMSGSIZE
+#define EPROTOTYPE       WSAEPROTOTYPE
+#define ENOPROTOOPT      WSAENOPROTOOPT
+#define EPROTONOSUPPORT  WSAEPROTONOSUPPORT
+#define ESOCKTNOSUPPORT  WSAESOCKTNOSUPPORT
+#define EOPNOTSUPP       WSAEOPNOTSUPP
+#define EPFNOSUPPORT     WSAEPFNOSUPPORT
+#define EAFNOSUPPORT     WSAEAFNOSUPPORT
+#define EADDRINUSE       WSAEADDRINUSE
+#define EADDRNOTAVAIL    WSAEADDRNOTAVAIL
+#define ENETDOWN         WSAENETDOWN
+#define ENETUNREACH      WSAENETUNREACH
+#define ENETRESET        WSAENETRESET
+#define ECONNABORTED     WSAECONNABORTED
+#define ECONNRESET       WSAECONNRESET
+#define ENOBUFS          WSAENOBUFS
+#define EISCONN          WSAEISCONN
+#define ENOTCONN         WSAENOTCONN
+#define ESHUTDOWN        WSAESHUTDOWN
+#define ETOOMANYREFS     WSAETOOMANYREFS
+#define ETIMEDOUT        WSAETIMEDOUT
+#define ECONNREFUSED     WSAECONNREFUSED
+#define ELOOP            WSAELOOP
+#define ENAMETOOLONG     WSAENAMETOOLONG
+#define EHOSTDOWN        WSAEHOSTDOWN
+#define EHOSTUNREACH     WSAEHOSTUNREACH
+#define ENOTEMPTY        WSAENOTEMPTY
+#define EPROCLIM         WSAEPROCLIM
+#define EUSERS           WSAEUSERS
+#define EDQUOT           WSAEDQUOT
+#define ESTALE           WSAESTALE
+#define EREMOTE          WSAEREMOTE
+#endif
+
+
 #endif /* __SETUP_ONCE_H */
 
diff --git a/tests/server/util.h b/tests/server/util.h
index a78a485f1..2848560bb 100644
--- a/tests/server/util.h
+++ b/tests/server/util.h
@@ -49,12 +49,6 @@ void win32_perror (const char *msg);
 #endif  /* WIN32 */
 
 #ifdef USE_WINSOCK
-#define EINPROGRESS  WSAEINPROGRESS
-#define EWOULDBLOCK  WSAEWOULDBLOCK
-#define EISCONN      WSAEISCONN
-#define ENOTSOCK     WSAENOTSOCK
-#define ECONNREFUSED WSAECONNREFUSED
-
 void win32_init(void);
 void win32_cleanup(void);
 #endif  /* USE_WINSOCK */