diff --git a/Makefile.in b/Makefile.in
index 5bee418..479df07 100755
--- a/Makefile.in
+++ b/Makefile.in
@@ -34,7 +34,7 @@ SERVERAPP_HEADERS = src/apps/relay/userdb.h src/apps/relay/tls_listener.h src/ap
 SERVERAPP_MODS = src/apps/relay/mainrelay.c src/apps/relay/netengine.c src/apps/relay/libtelnet.c src/apps/relay/turn_admin_server.c src/apps/relay/userdb.c src/apps/relay/tls_listener.c src/apps/relay/dtls_listener.c ${HIREDIS_MODS} ${USERDB_MODS}
 SERVERAPP_DEPS = ${SERVERTURN_MODS} ${SERVERTURN_DEPS} ${SERVERAPP_MODS} ${SERVERAPP_HEADERS} ${COMMON_DEPS} ${IMPL_DEPS} lib/libturnclient.a
 
-TURN_BUILD_RESULTS = bin/turnutils_stunclient bin/turnutils_rfc5769check bin/turnutils_uclient bin/turnserver bin/turnutils_peer lib/libturnclient.a include/turn/ns_turn_defs.h sqlite_empty_db
+TURN_BUILD_RESULTS = bin/turnutils_natdiscovery bin/turnutils_stunclient bin/turnutils_rfc5769check bin/turnutils_uclient bin/turnserver bin/turnutils_peer lib/libturnclient.a include/turn/ns_turn_defs.h sqlite_empty_db
 
 all:	${TURN_BUILD_RESULTS}
 
@@ -54,6 +54,11 @@ bin/turnutils_uclient:	${COMMON_DEPS} src/apps/uclient/session.h lib/libturnclie
 	${MKBUILDDIR} bin
 	${CC} ${CPPFLAGS} ${CFLAGS} src/apps/uclient/uclient.c src/apps/uclient/startuclient.c src/apps/uclient/mainuclient.c ${COMMON_MODS} -o $@ -Llib -lturnclient -Llib ${LDFLAGS}  
 
+bin/turnutils_natdiscovery:	${COMMON_DEPS} lib/libturnclient.a src/apps/natdiscovery/natdiscovery.c
+	pwd
+	${MKBUILDDIR} bin
+	${CC} ${CPPFLAGS} ${CFLAGS} src/apps/natdiscovery/natdiscovery.c ${COMMON_MODS} -o $@ -Llib -lturnclient -Llib ${LDFLAGS}
+
 bin/turnutils_stunclient:	${COMMON_DEPS} lib/libturnclient.a src/apps/stunclient/stunclient.c 
 	pwd
 	${MKBUILDDIR} bin
@@ -125,11 +130,13 @@ install:	all ${MAKE_DEPS}
 	${INSTALL_PROGRAM} bin/turnutils_uclient ${DESTDIR}${BINDIR}
 	${INSTALL_PROGRAM} bin/turnutils_peer ${DESTDIR}${BINDIR}
 	${INSTALL_PROGRAM} bin/turnutils_stunclient ${DESTDIR}${BINDIR}
+	${INSTALL_PROGRAM} bin/turnutils_natdiscovery ${DESTDIR}${BINDIR}
 	${INSTALL_MAN} man/man1/turnserver.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/turnadmin.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/turnutils.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/turnutils_uclient.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/turnutils_stunclient.1 ${DESTDIR}${MANPREFIX}/man/man1/
+	${INSTALL_MAN} man/man1/turnutils_natdiscovery.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/turnutils_peer.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_MAN} man/man1/coturn.1 ${DESTDIR}${MANPREFIX}/man/man1/
 	${INSTALL_STATIC_LIB} lib/libturnclient.a ${DESTDIR}${LIBDIR}
@@ -169,11 +176,13 @@ deinstall:	${MAKE_DEPS}
 	${RMCMD} ${DESTDIR}${BINDIR}/turnutils_peer
 	${RMCMD} ${DESTDIR}${BINDIR}/turnutils_uclient
 	${RMCMD} ${DESTDIR}${BINDIR}/turnutils_stunclient
+	${RMCMD} ${DESTDIR}${BINDIR}/turnutils_natdiscovery
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnserver.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnadmin.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnutils.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnutils_uclient.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnutils_stunclient.1
+	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnutils_natdiscovery.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/turnutils_peer.1
 	${RMCMD} ${DESTDIR}${MANPREFIX}/man/man1/coturn.1
 	${RMCMD} ${DESTDIR}${LIBDIR}/libturnclient.a
diff --git a/src/apps/natdiscovery/natdiscovery.c b/src/apps/natdiscovery/natdiscovery.c
new file mode 100644
index 0000000..10b675e
--- /dev/null
+++ b/src/apps/natdiscovery/natdiscovery.c
@@ -0,0 +1,452 @@
+/*
+ * Copyright (C) 2011, 2012, 2013 Citrix Systems
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <err.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "ns_turn_utils.h"
+#include "apputils.h"
+#include "stun_buffer.h"
+
+#ifdef __cplusplus
+#include "TurnMsgLib.h"
+#endif
+
+////////////////////////////////////////////////////
+
+static int udp_fd = -1;
+static ioa_addr real_local_addr;
+static int counter = 0;
+
+#ifdef __cplusplus
+
+static int run_stunclient(ioa_addr *remote_addr, ioa_addr *reflexive_addr, ioa_addr *other_addr, int *port, int *rfc5780, int response_port, int change_ip, int change_port, int padding)
+{
+
+
+	if (response_port >= 0) {
+		addr_set_port(&real_local_addr, response_port);
+	}
+	udp_fd = socket(remote_addr->ss.sa_family, SOCK_DGRAM, 0);
+	if (udp_fd < 0)
+		err(-1, NULL);
+
+	if (!addr_any(&real_local_addr)) {
+		if (addr_bind(udp_fd, &real_local_addr,0,1,UDP_SOCKET) < 0)
+			err(-1, NULL);
+	}
+
+
+
+
+	turn::StunMsgRequest req(STUN_METHOD_BINDING);
+
+	req.constructBindingRequest();
+
+	if (response_port >= 0) {
+	  turn::StunAttrResponsePort rpa;
+		rpa.setResponsePort((u16bits)response_port);
+		try {
+			req.addAttr(rpa);
+		} catch(turn::WrongStunAttrFormatException &ex1) {
+			printf("Wrong rp attr format\n");
+			exit(-1);
+		} catch(turn::WrongStunBufferFormatException &ex2) {
+			printf("Wrong stun buffer format (1)\n");
+			exit(-1);
+		} catch(...) {
+			printf("Wrong something (1)\n");
+			exit(-1);
+		}
+	}
+	if (change_ip || change_port) {
+		turn::StunAttrChangeRequest cra;
+		cra.setChangeIp(change_ip);
+		cra.setChangePort(change_port);
+		try {
+			req.addAttr(cra);
+		} catch(turn::WrongStunAttrFormatException &ex1) {
+			printf("Wrong cr attr format\n");
+			exit(-1);
+		} catch(turn::WrongStunBufferFormatException &ex2) {
+			printf("Wrong stun buffer format (2)\n");
+			exit(-1);
+		} catch(...) {
+			printf("Wrong something (2)\n");
+			exit(-1);
+		}
+	}
+	if (padding) {
+		turn::StunAttrPadding pa;
+		pa.setPadding(1500);
+		try {
+			req.addAttr(pa);
+		} catch(turn::WrongStunAttrFormatException &ex1) {
+			printf("Wrong p attr format\n");
+			exit(-1);
+		} catch(turn::WrongStunBufferFormatException &ex2) {
+			printf("Wrong stun buffer format (3)\n");
+			exit(-1);
+		} catch(...) {
+			printf("Wrong something (3)\n");
+			exit(-1);
+		}
+	}
+
+	{
+		int len = 0;
+		int slen = get_ioa_addr_len(remote_addr);
+
+		do {
+			len = sendto(udp_fd, req.getRawBuffer(), req.getSize(), 0, (struct sockaddr*) remote_addr, (socklen_t) slen);
+		} while (len < 0 && ((errno == EINTR) || (errno == ENOBUFS) || (errno == EAGAIN)));
+
+		if (len < 0)
+			err(-1, NULL);
+
+	}
+
+	if (addr_get_from_sock(udp_fd, &real_local_addr) < 0) {
+		printf("%s: Cannot get address from local socket\n", __FUNCTION__);
+	} else {
+		*port = addr_get_port(&real_local_addr);
+	}
+
+	{
+		int len = 0;
+		stun_buffer buf;
+		u08bits *ptr = buf.buf;
+		int recvd = 0;
+		const int to_recv = sizeof(buf.buf);
+
+		do {
+			len = recv(udp_fd, ptr, to_recv - recvd, 0);
+			if (len > 0) {
+				recvd += len;
+				ptr += len;
+				break;
+			}
+		} while (len < 0 && (errno == EINTR));
+
+		if (recvd > 0)
+			len = recvd;
+		buf.len = len;
+
+		try {
+			turn::StunMsgResponse res(buf.buf, sizeof(buf.buf), (size_t)buf.len, true);
+
+			if (res.isCommand()) {
+
+				if(res.isSuccess()) {
+
+					if (res.isBindingResponse()) {
+
+						turn::StunAttrIterator iter(res,STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS);
+						if (!iter.eof()) {
+
+							turn::StunAttrAddr addr(iter);
+							addr.getAddr(*reflexive_addr);
+
+							turn::StunAttrIterator iter1(res,STUN_ATTRIBUTE_OTHER_ADDRESS);
+							if (!iter1.eof()) {
+								*rfc5780 = 1;
+								printf("\n========================================\n");
+								printf("RFC 5780 response %d\n",++counter);
+								turn::StunAttrAddr addr1(iter1);
+								addr1.getAddr(*other_addr);
+								turn::StunAttrIterator iter2(res,STUN_ATTRIBUTE_RESPONSE_ORIGIN);
+								if (!iter2.eof()) {
+									ioa_addr response_origin;
+									turn::StunAttrAddr addr2(iter2);
+									addr2.getAddr(response_origin);
+									addr_debug_print(1, &response_origin, "Response origin: ");
+								}
+								addr_debug_print(1, other_addr, "Other addr: ");
+							}
+							addr_debug_print(1, &reflexive_addr, "UDP reflexive addr");
+
+						} else {
+							printf("Cannot read the response\n");
+						}
+					} else {
+						printf("Wrong type of response\n");
+					}
+				} else {
+					int err_code = res.getError();
+					std::string reason = res.getReason();
+
+					printf("The response is an error %d (%s)\n", err_code, reason.c_str());
+				}
+			} else {
+				printf("The response is not a reponse message\n");
+			}
+		} catch(...) {
+			printf("The response is not a well formed STUN message\n");
+		}
+	}
+	close(udp_fd);
+
+	return 0;
+}
+
+#else
+
+static int run_stunclient(ioa_addr *remote_addr, ioa_addr *reflexive_addr, ioa_addr *other_addr, int *port, int *rfc5780, int response_port, int change_ip, int change_port, int padding)
+{
+
+	stun_buffer buf;
+
+	udp_fd = socket(remote_addr->ss.sa_family, CLIENT_DGRAM_SOCKET_TYPE, CLIENT_DGRAM_SOCKET_PROTOCOL);
+	if (udp_fd < 0)
+		err(-1, NULL);
+
+	if (!addr_any(&real_local_addr)) {
+		if (response_port >= 0) {
+			addr_set_port(&real_local_addr, response_port);
+                } 
+		if (addr_bind(udp_fd, &real_local_addr,0,1,UDP_SOCKET) < 0) {
+			err(-1, NULL);
+                }
+	}
+
+
+	stun_prepare_binding_request(&buf);
+
+	if (response_port >= 0) {
+		stun_attr_add_response_port_str((u08bits*) (buf.buf), (size_t*) &(buf.len), (u16bits) response_port);
+	}
+	if (change_ip || change_port) {
+		stun_attr_add_change_request_str((u08bits*) buf.buf, (size_t*) &(buf.len), change_ip, change_port);
+	}
+	if (padding) {
+		if(stun_attr_add_padding_str((u08bits*) buf.buf, (size_t*) &(buf.len), 1500)<0) {
+			printf("%s: ERROR: Cannot add padding\n",__FUNCTION__);
+		}
+	}
+
+	{
+		int len = 0;
+		int slen = get_ioa_addr_len(remote_addr);
+
+		do {
+			len = sendto(udp_fd, buf.buf, buf.len, 0, (struct sockaddr*) remote_addr, (socklen_t) slen);
+		} while (len < 0 && ((errno == EINTR) || (errno == ENOBUFS) || (errno == EAGAIN)));
+
+		if (len < 0)
+			err(-1, NULL);
+
+	}
+
+	if (addr_get_from_sock(udp_fd, &real_local_addr) < 0) {
+		printf("%s: Cannot get address from local socket\n", __FUNCTION__);
+	} else {
+		*port = addr_get_port(&real_local_addr);
+	}
+
+	
+	{
+		int len = 0;
+		u08bits *ptr = buf.buf;
+		int recvd = 0;
+		const int to_recv = sizeof(buf.buf);
+
+		do {
+			len = recv(udp_fd, ptr, to_recv - recvd, 0);
+			if (len > 0) {
+				recvd += len;
+				ptr += len;
+				break;
+			}
+		} while (len < 0 && ((errno == EINTR) || (errno == EAGAIN)));
+
+		if (recvd > 0)
+			len = recvd;
+		buf.len = len;
+
+		if (stun_is_command_message(&buf)) {
+
+			if (stun_is_response(&buf)) {
+
+				if (stun_is_success_response(&buf)) {
+
+					if (stun_is_binding_response(&buf)) {
+
+						addr_set_any(reflexive_addr);
+						if (stun_attr_get_first_addr(&buf, STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS, reflexive_addr, NULL) >= 0) {
+
+							stun_attr_ref sar = stun_attr_get_first_by_type_str(buf.buf, buf.len, STUN_ATTRIBUTE_OTHER_ADDRESS);
+							if (sar) {
+								*rfc5780 = 1;
+								printf("\n========================================\n");
+								printf("RFC 5780 response %d\n",++counter);
+								stun_attr_get_addr_str((u08bits *) buf.buf, (size_t) buf.len, sar, other_addr, NULL);
+								sar = stun_attr_get_first_by_type_str(buf.buf, buf.len, STUN_ATTRIBUTE_RESPONSE_ORIGIN);
+								if (sar) {
+									ioa_addr response_origin;
+									stun_attr_get_addr_str((u08bits *) buf.buf, (size_t) buf.len, sar, &response_origin, NULL);
+									addr_debug_print(1, &response_origin, "Response origin: ");
+								}
+								addr_debug_print(1, other_addr, "Other addr: ");
+							}
+							addr_debug_print(1, reflexive_addr, "UDP reflexive addr");
+
+						} else {
+							printf("Cannot read the response\n");
+						}
+					} else {
+						printf("Wrong type of response\n");
+					}
+				} else {
+					int err_code = 0;
+					u08bits err_msg[1025] = "\0";
+					size_t err_msg_size = sizeof(err_msg);
+					if (stun_is_error_response(&buf, &err_code, err_msg, err_msg_size)) {
+						printf("The response is an error %d (%s)\n", err_code, (char*) err_msg);
+					} else {
+						printf("The response is an unrecognized error\n");
+					}
+				}
+			} else {
+				printf("The response is not a reponse message\n");
+			}
+		} else {
+			printf("The response is not a STUN message\n");
+		}
+	}
+
+	socket_closesocket(udp_fd);
+	return 0;
+}
+#endif
+
+//////////////// local definitions /////////////////
+
+static char Usage[] =
+  "Usage: stunclient [options] address\n"
+  "Options:\n"
+  "        -p      STUN server port (Default: 3478)\n"
+  "        -L      Local address to use (optional)\n"
+  "        -f      Force RFC 5780 processing\n";
+
+//////////////////////////////////////////////////
+
+int main(int argc, char **argv)
+{
+  int port = DEFAULT_STUN_PORT;
+  char local_addr[256]="\0";
+  int c=0;
+  int forceRfc5780 = 0;
+  ioa_addr other_addr, reflexive_addr, tmp_addr, remote_addr;
+  
+
+  set_logfile("stdout");
+  set_system_parameters(0);
+  
+  ns_bzero(local_addr, sizeof(local_addr));
+  addr_set_any(&remote_addr);
+  addr_set_any(&other_addr);
+  addr_set_any(&reflexive_addr);
+  addr_set_any(&tmp_addr);
+
+
+  while ((c = getopt(argc, argv, "p:L:f")) != -1) {
+    switch(c) {
+    case 'f':
+	    forceRfc5780 = 1;
+	    break;
+    case 'p':
+      port = atoi(optarg);
+      break;
+    case 'L':
+      STRCPY(local_addr, optarg);
+      break;
+    default:
+      fprintf(stderr,"%s\n", Usage);
+      exit(1);
+    }
+  }
+
+  if(optind>=argc) {
+    fprintf(stderr, "%s\n", Usage);
+    exit(-1);
+  }
+
+  addr_set_any(&real_local_addr);
+
+  if(local_addr[0]) {
+      if(make_ioa_addr((const u08bits*)local_addr, 0, &real_local_addr)<0) {
+        err(-1,NULL);
+      }
+  }
+
+  int local_port = -1;
+  int rfc5780 = 0;
+
+  if (make_ioa_addr((const u08bits*)argv[optind], port, &remote_addr) < 0)
+		err(-1, NULL);
+
+
+  run_stunclient(&remote_addr, &reflexive_addr, &other_addr, &local_port, &rfc5780,-1,0,0,0);
+  if (addr_eq(&real_local_addr,&reflexive_addr)){
+  	printf("No NAT! (Endpoint Independent Mapping)");
+  }
+  if(rfc5780 || forceRfc5780) {
+          if(!addr_any(&other_addr)){
+
+  		  addr_cpy(&tmp_addr, &reflexive_addr);
+
+  		  addr_cpy(&remote_addr, &other_addr);
+                  addr_set_port(&remote_addr, port);
+
+	          run_stunclient(&remote_addr, &reflexive_addr, &other_addr, &local_port, &rfc5780,-1,0,0,0);
+
+                  if(addr_eq(&tmp_addr,&reflexive_addr)){
+                          printf("NAT with Enpoint Independent Mapping!\n"); 
+                  } else {
+  		  	  addr_cpy(&tmp_addr, &reflexive_addr);
+  		          addr_cpy(&remote_addr, &other_addr);
+	          	  run_stunclient(&remote_addr, &reflexive_addr, &other_addr, &local_port, &rfc5780,-1,0,0,0);
+			  if(addr_eq(&tmp_addr,&reflexive_addr)){
+				printf("NAT with Address Dependent Mapping!\n"); 
+			  } else {
+				printf("NAT with Address and Port Dependent Mapping!\n"); 
+			  }
+                  };
+          }
+  }
+
+  socket_closesocket(udp_fd);
+
+  return 0;
+}