diff --git a/src/backend/port/win32/socket.c b/src/backend/port/win32/socket.c
index 6fbd1ed6fb..0f28c07ed1 100644
--- a/src/backend/port/win32/socket.c
+++ b/src/backend/port/win32/socket.c
@@ -123,10 +123,14 @@ TranslateSocketError(void)
 		case WSAEHOSTUNREACH:
 		case WSAEHOSTDOWN:
 		case WSAHOST_NOT_FOUND:
+			errno = EHOSTUNREACH;
+			break;
 		case WSAENETDOWN:
-		case WSAENETUNREACH:
 		case WSAENETRESET:
-			errno = EHOSTUNREACH;
+			errno = ENETDOWN;
+			break;
+		case WSAENETUNREACH:
+			errno = ENETUNREACH;
 			break;
 		case WSAENOTCONN:
 		case WSAESHUTDOWN:
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index d0b368530e..8937f223a8 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -712,9 +712,7 @@ errcode_for_socket_access(void)
 	{
 			/* Loss of connection */
 		case EPIPE:
-#ifdef ECONNRESET
-		case ECONNRESET:
-#endif
+		case ALL_CONNECTION_LOSS_ERRNOS:
 			edata->sqlerrcode = ERRCODE_CONNECTION_FAILURE;
 			break;
 
diff --git a/src/bin/pg_dump/parallel.c b/src/bin/pg_dump/parallel.c
index f0587f41e4..b8ab939179 100644
--- a/src/bin/pg_dump/parallel.c
+++ b/src/bin/pg_dump/parallel.c
@@ -1825,7 +1825,7 @@ piperead(int s, char *buf, int len)
 {
 	int			ret = recv(s, buf, len, 0);
 
-	if (ret < 0 && WSAGetLastError() == WSAECONNRESET)
+	if (ret < 0 && errno_is_connection_loss(WSAGetLastError()))
 	{
 		/* EOF on the pipe! */
 		ret = 0;
diff --git a/src/include/port.h b/src/include/port.h
index 84bf2c363f..ffa21e782a 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -99,6 +99,30 @@ extern void pgfnames_cleanup(char **filenames);
 )
 #endif
 
+/* Test for all errnos that report loss of an established TCP connection */
+static inline bool
+errno_is_connection_loss(int e)
+{
+	if (e == ECONNRESET ||
+		e == ECONNABORTED ||
+		e == EHOSTUNREACH ||
+		e == ENETDOWN ||
+		e == ENETUNREACH)
+		return true;
+	return false;
+}
+
+/*
+ * To test for connection-loss errnos in a switch statement, write
+ * "case ALL_CONNECTION_LOSS_ERRNOS:".
+ */
+#define ALL_CONNECTION_LOSS_ERRNOS \
+	ECONNRESET: \
+	case ECONNABORTED: \
+	case EHOSTUNREACH: \
+	case ENETDOWN: \
+	case ENETUNREACH
+
 /* Portable locale initialization (in exec.c) */
 extern void set_pglocale_pgservice(const char *argv0, const char *app);
 
diff --git a/src/include/port/win32_port.h b/src/include/port/win32_port.h
index 8b6576b23d..7ce8c87e8d 100644
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -351,6 +351,10 @@ extern int	pgwin32_safestat(const char *path, struct stat *buf);
 #define EADDRNOTAVAIL WSAEADDRNOTAVAIL
 #undef EHOSTUNREACH
 #define EHOSTUNREACH WSAEHOSTUNREACH
+#undef ENETDOWN
+#define ENETDOWN WSAENETDOWN
+#undef ENETUNREACH
+#define ENETUNREACH WSAENETUNREACH
 #undef ENOTCONN
 #define ENOTCONN WSAENOTCONN
 
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index ff840b7730..ecc3b4ba0b 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -679,11 +679,9 @@ retry3:
 		if (SOCK_ERRNO == EWOULDBLOCK)
 			return someread;
 #endif
-		/* We might get ECONNRESET here if using TCP and backend died */
-#ifdef ECONNRESET
-		if (SOCK_ERRNO == ECONNRESET)
+		/* We might get ECONNRESET etc here if using TCP and backend died */
+		if (errno_is_connection_loss(SOCK_ERRNO))
 			goto definitelyFailed;
-#endif
 		/* pqsecure_read set the error message for us */
 		return -1;
 	}
@@ -769,11 +767,9 @@ retry4:
 		if (SOCK_ERRNO == EWOULDBLOCK)
 			return 0;
 #endif
-		/* We might get ECONNRESET here if using TCP and backend died */
-#ifdef ECONNRESET
-		if (SOCK_ERRNO == ECONNRESET)
+		/* We might get ECONNRESET etc here if using TCP and backend died */
+		if (errno_is_connection_loss(SOCK_ERRNO))
 			goto definitelyFailed;
-#endif
 		/* pqsecure_read set the error message for us */
 		return -1;
 	}
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index d609a38bbe..3c89c34f80 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -204,7 +204,7 @@ rloop:
 			{
 				result_errno = SOCK_ERRNO;
 				if (result_errno == EPIPE ||
-					result_errno == ECONNRESET)
+					errno_is_connection_loss(result_errno))
 					printfPQExpBuffer(&conn->errorMessage,
 									  libpq_gettext("server closed the connection unexpectedly\n"
 													"\tThis probably means the server terminated abnormally\n"
@@ -311,7 +311,8 @@ pgtls_write(PGconn *conn, const void *ptr, size_t len)
 			if (n < 0)
 			{
 				result_errno = SOCK_ERRNO;
-				if (result_errno == EPIPE || result_errno == ECONNRESET)
+				if (result_errno == EPIPE ||
+					errno_is_connection_loss(result_errno))
 					printfPQExpBuffer(&conn->errorMessage,
 									  libpq_gettext("server closed the connection unexpectedly\n"
 													"\tThis probably means the server terminated abnormally\n"
diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index 3311fd7a5b..f13651b544 100644
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -261,14 +261,12 @@ pqsecure_raw_read(PGconn *conn, void *ptr, size_t len)
 				/* no error message, caller is expected to retry */
 				break;
 
-#ifdef ECONNRESET
-			case ECONNRESET:
+			case ALL_CONNECTION_LOSS_ERRNOS:
 				printfPQExpBuffer(&conn->errorMessage,
 								  libpq_gettext("server closed the connection unexpectedly\n"
 												"\tThis probably means the server terminated abnormally\n"
 												"\tbefore or while processing the request.\n"));
 				break;
-#endif
 
 			default:
 				printfPQExpBuffer(&conn->errorMessage,
@@ -374,11 +372,9 @@ retry_masked:
 				/* Set flag for EPIPE */
 				REMEMBER_EPIPE(spinfo, true);
 
-#ifdef ECONNRESET
 				/* FALL THRU */
 
-			case ECONNRESET:
-#endif
+			case ALL_CONNECTION_LOSS_ERRNOS:
 				printfPQExpBuffer(&conn->errorMessage,
 								  libpq_gettext("server closed the connection unexpectedly\n"
 												"\tThis probably means the server terminated abnormally\n"
diff --git a/src/interfaces/libpq/win32.h b/src/interfaces/libpq/win32.h
index c42d7abfe3..eba4c2a358 100644
--- a/src/interfaces/libpq/win32.h
+++ b/src/interfaces/libpq/win32.h
@@ -16,15 +16,6 @@
 #undef EAGAIN					/* doesn't apply on sockets */
 #undef EINTR
 #define EINTR WSAEINTR
-#ifndef EWOULDBLOCK
-#define EWOULDBLOCK WSAEWOULDBLOCK
-#endif
-#ifndef ECONNRESET
-#define ECONNRESET WSAECONNRESET
-#endif
-#ifndef EINPROGRESS
-#define EINPROGRESS WSAEINPROGRESS
-#endif
 
 /*
  * support for handling Windows Socket errors
diff --git a/src/port/strerror.c b/src/port/strerror.c
index 375edb0f5a..c179c9ae60 100644
--- a/src/port/strerror.c
+++ b/src/port/strerror.c
@@ -146,16 +146,12 @@ get_errno_symbol(int errnum)
 			return "EBUSY";
 		case ECHILD:
 			return "ECHILD";
-#ifdef ECONNABORTED
 		case ECONNABORTED:
 			return "ECONNABORTED";
-#endif
 		case ECONNREFUSED:
 			return "ECONNREFUSED";
-#ifdef ECONNRESET
 		case ECONNRESET:
 			return "ECONNRESET";
-#endif
 		case EDEADLK:
 			return "EDEADLK";
 		case EDOM:
@@ -166,10 +162,8 @@ get_errno_symbol(int errnum)
 			return "EFAULT";
 		case EFBIG:
 			return "EFBIG";
-#ifdef EHOSTUNREACH
 		case EHOSTUNREACH:
 			return "EHOSTUNREACH";
-#endif
 		case EIDRM:
 			return "EIDRM";
 		case EINPROGRESS:
@@ -198,6 +192,10 @@ get_errno_symbol(int errnum)
 			return "EMSGSIZE";
 		case ENAMETOOLONG:
 			return "ENAMETOOLONG";
+		case ENETDOWN:
+			return "ENETDOWN";
+		case ENETUNREACH:
+			return "ENETUNREACH";
 		case ENFILE:
 			return "ENFILE";
 		case ENOBUFS: