diff --git a/cygwin/README.bintarball.txt b/cygwin/README.bintarball.txt

index b1b66e0..9fa5222 100644

--- a/cygwin/README.bintarball.txt

+++ b/cygwin/README.bintarball.txt

@@ -129,10 +129,6 @@ $ (set -o xtrace ; cd / && tar -tf ~/download/${bintarball.base_filename}.tar.bz

 $ /sbin/msnfs41client run_daemon

 # Mount a filesystem and use it

-# - requires that NFSv4 server accepts connections from a TCP port

-# number > 1024, which can be archived on Linux with the "insecure"

-# export option in /etc/exports, or "resvport" on Solaris/Illumos

-# (see nfs(5))

 $ /sbin/nfs_mount -o rw N 10.49.20.110:/net_tmpfs2

 Successfully mounted '10.49.20.110@2049' to drive 'N:'

 $ cd /cygdrive/n/

@@ -230,15 +226,15 @@ $ /sbin/nfs_mount

   A::EVERYONE@:rtcy

   ---- snip ----

-- nfs_mount only works when the NFSv4 server allows connections from

-  ports >= 1024, as Windows does not allow the Windows NFSv4 client

-  to use a "privileged port" (i.e. TCP port number < 1024)).

+- nfs_mount.exe vs. reserved ports:

   By default the NFSv4 server on Solaris, Illumos, Linux

   etc. only accepts connections if the NFSv4 client uses a

-  "privileged (TCP) port", i.e. a port number < 1024.

-  This can be worked around by using the "insecure" export option in

-  Linux /etc/exports, which allows connections from ports >= 1024,

-  and for Solaris/Illumos see nfs(5), option "resvport".

 #

diff --git a/libtirpc/src/bindresvport.c b/libtirpc/src/bindresvport.c

index 01d1921..be56a6c 100644

--- a/libtirpc/src/bindresvport.c

+++ b/libtirpc/src/bindresvport.c

@@ -1,5 +1,6 @@

  * Copyright (c) 2009, Sun Microsystems, Inc.

+ * Copyright (c) 2024, Roland Mainz <roland.mainz@nrubsig.org>

 #include <wintirpc.h>

 #include <sys/types.h>

-//#include <sys/socket.h>

-

-//#include <netinet/in.h>

+#ifndef _WIN32

+#include <sys/socket.h>

+#include <netinet/in.h>

+#endif

 #include <errno.h>

 #include <string.h>

-//#include <unistd.h>

+#ifndef _WIN32

+#include <unistd.h>

+#endif

 #include <rpc/rpc.h>

 /*

  * Bind a socket to a privileged IP port

  */

@@ -139,18 +150,147 @@ bindresvport_sa(sd, sa)

+#define STARTPORT 600

+#define ENDPORT (IPPORT_RESERVED - 1)

+/* Debug */

+#if 0

+#define BRP_D(x) x

 #else

-/*----------------------

+/* fixme: not threadsafe, we should use |portnum_lock| */

+static int bindresvport_sa_last_n = 0;

 int

 bindresvport_sa(int sd, struct sockaddr *sa)

 {

-	fprintf(stderr, "Do-nothing bindresvport_sa!\n");

-	return 0;

+	int res = 1;

+	int ioctlres;

+	int lasterr;

+	SOCKET sd_sock;

+	INET_PORT_RANGE portRange;

+	INET_PORT_RESERVATION_INSTANCE portRes;

+	DWORD bytesReturned;

+	BRP_D((void)fprintf(stdout,

+		"--> bindresvport_sa(sd=%d,sa=0x%p): "

+		"bindresvport_sa_last_n=%d\n",

+		sd, sa, bindresvport_sa_last_n));

+	sd_sock = _get_osfhandle(sd);

+	for (n = 0 ; n < NPORTS ; n++) {

+		currport = ((n+bindresvport_sa_last_n)%NPORTS)+STARTPORT;

+		portRange.StartPort = htons(currport);

+		portRange.NumberOfPorts = 1;

+		(void)memset(&portRes, 0, sizeof(portRes));

+		bytesReturned = 0;

+

+		BRP_D((void)fprintf(stdout,

+			"bindresvport_sa(sd=%d,sa=0x%p): "

+			"trying n=%d, bindresvport_sa_last_n=%d, port=%d ...\n",

+			sd, sa, n, bindresvport_sa_last_n,

+			(int)ntohs(portRange.StartPort)));

+		ioctlres = WSAIoctl(sd_sock,

+			SIO_ACQUIRE_PORT_RESERVATION,

+			(LPVOID)&portRange,

+			sizeof(INET_PORT_RANGE),

+			(LPVOID)&portRes,

+		if ((ioctlres != 0) && (lasterr == WSAEADDRINUSE)) {

+			BRP_D((void)fprintf(stderr,

+				"bindresvport_sa(sd=%d,sa=0x%p): "

+				"port=%d in use, trying next port...\n",

+		if (ioctlres != 0) {

+			warnx("bindresvport_sa(sd=%d,sa=0x%p): "

+				"SIO_ACQUIRE_PORT_RESERVATION failed "

+				"with error = %d\n",

+				sd, sa, lasterr);

+		/* Success */

+		bindresvport_sa_last_n = n+1;

+		break;

+	}

+

+	if (n == NPORTS) {

+		warnx("bindresvport_sa(sd=%d,sa=0x%p): "

+			"n(=%d) == NPORTS(=%d), "

+			"no reserved port available\n", n, NPORTS);

+		res = 1;

+		goto out;

+	}

+

+	BRP_D((void)fprintf(stdout, "bindresvport_sa(sd=%d,sa=0x%p): "

+		"SIO_ACQUIRE_PORT_RESERVATION succeeded, "

+		"bytesReturned = %u, StartPort=%d, NumberOfPorts=%d, "

+		"Token=0x%llx\n",

+		sd, sa, bytesReturned, (int)ntohs(portRes.StartPort),

+		portRes.NumberOfPorts, (long long)portRes.Token));

+

+	bytesReturned = 0;

+	ioctlres = WSAIoctl(sd_sock, SIO_ASSOCIATE_PORT_RESERVATION,

+		(LPVOID)&portRes.Token, sizeof(ULONG64), NULL, 0,

+		&bytesReturned, NULL, NULL);

+	lasterr = WSAGetLastError();

+	if (ioctlres != 0) {

+		warnx("bindresvport_sa(sd=%d,sa=0x%p): "

+			"WSAIoctl(SIO_ASSOCIATE_PORT_RESERVATION) "

+			"failed with error = %d\n",

+			sd, sa, lasterr);

+		res = 1;

+		goto out;

+	}

+

+	BRP_D((void)fprintf(stdout, "bindresvport_sa(sd=%d,sa=0x%p): "

+		"WSAIoctl(SIO_ASSOCIATE_PORT_RESERVATION) succeeded, "

+		"bytesReturned = %u\n",

+		sd, sa, bytesReturned));

+	res = 0;

+

+	/*

+	 * FIXME: We should call |SIO_RELEASE_PORT_RESERVATION|,

+	 * but we cannot do that while |sd| is open and using the

+	 * reservation.

+	 * So basically we to store the token, and then use a second

+	 * socket, with matching protocol&co attributes, just to

+	 * release the reservation.

+	 *

+	 * A possible solution might be to derive a "control socket"

+	 * from |sd|, and do the reservation ioctl using that socket.

+	 *

+	 * For now we ignore this, and assume noone will do more

+	 * than |NPORTS| { mount, umount }-sequences during

+	 * nfsd.exe/nfsd_debug.exe lifetime

+	 */

+out:

+	BRP_D((void)fprintf(stdout,

+		"<-- bindresvport_sa(sd=%d,sa=0x%p) returning res=%d\n",

+		sd, sa, res));

+	return res;

 }

 #else

--------------------------*/

+

 #define IP_PORTRANGE 19

 #define IP_PORTRANGE_LOW 2

@@ -174,29 +314,16 @@ bindresvport_sa(sd, sa)

 	int proto, portrange, portlow;

 	u_int16_t *portp;

 	socklen_t salen;

-#ifdef _WIN32

-		WSAPROTOCOL_INFO proto_info;

-		int proto_info_size = sizeof(proto_info);

-#endif

 	if (sa == NULL) {

 		salen = sizeof(myaddr);

 		sa = (struct sockaddr *)&myaddr;

-#ifdef _WIN32

-		memset(sa, 0, salen);

-		if (error = wintirpc_getsockopt(sd, SOL_SOCKET, SO_PROTOCOL_INFO, (char *)&proto_info, &proto_info_size) == SOCKET_ERROR) {

-			int sockerr = WSAGetLastError();

-			return -1;

-		}

-		af = proto_info.iAddressFamily;

-#else

 		if (wintirpc_getsockname(sd, sa, &salen) == -1)

 			return -1;	/* errno is correctly set */

 		af = sa->sa_family;

 		memset(sa, 0, salen);

-#endif

 	} else

 		af = sa->sa_family;

@@ -268,7 +395,4 @@ bindresvport_sa(sd, sa)

 #endif

 	return (error);

 }

-/*

-#endif

-*/

 #endif