diff --git a/libknet/threads_heartbeat.c b/libknet/threads_heartbeat.c
index fef56a8a..d963c6fa 100644
--- a/libknet/threads_heartbeat.c
+++ b/libknet/threads_heartbeat.c
@@ -1,133 +1,134 @@
 /*
  * Copyright (C) 2010-2015 Red Hat, Inc.  All rights reserved.
  *
  * Authors: Fabio M. Di Nitto <fabbione@kronosnet.org>
  *          Federico Simoncelli <fsimon@kronosnet.org>
  *
  * This software licensed under GPL-2.0+, LGPL-2.0+
  */
 
 #include "config.h"
 
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
 #include <pthread.h>
 #include <time.h>
 
 #include "crypto.h"
 #include "link.h"
 #include "logging.h"
 #include "threads_common.h"
 #include "threads_heartbeat.h"
 
 static void _link_down(knet_handle_t knet_h, struct knet_host *dst_host, struct knet_link *dst_link)
 {
+	memset(&dst_link->pmtud_last, 0, sizeof(struct timespec));
 	dst_link->received_pong = 0;
 	dst_link->status.pong_last.tv_nsec = 0;
 	if (dst_link->status.connected == 1) {
 		log_info(knet_h, KNET_SUB_LINK, "host: %u link: %u is down",
 			 dst_host->host_id, dst_link->link_id);
 		_link_updown(knet_h, dst_host->host_id, dst_link->link_id, dst_link->status.enabled, 0);
 	}
 }
 
 static void _handle_check_each(knet_handle_t knet_h, struct knet_host *dst_host, struct knet_link *dst_link)
 {
 	int len;
 	ssize_t outlen = KNET_HEADER_PING_SIZE;
 	struct timespec clock_now, pong_last;
 	unsigned long long diff_ping;
 	unsigned char *outbuf = (unsigned char *)knet_h->pingbuf;
 
 	if (dst_link->transport_connected == 0) {
 		_link_down(knet_h, dst_host, dst_link);
 		return;
 	}
 
 	/* caching last pong to avoid race conditions */
 	pong_last = dst_link->status.pong_last;
 
 	if (clock_gettime(CLOCK_MONOTONIC, &clock_now) != 0) {
 		log_debug(knet_h, KNET_SUB_HEARTBEAT, "Unable to get monotonic clock");
 		return;
 	}
 
 	timespec_diff(dst_link->ping_last, clock_now, &diff_ping);
 
 	if (diff_ping >= (dst_link->ping_interval * 1000llu)) {
 		memmove(&knet_h->pingbuf->khp_ping_time[0], &clock_now, sizeof(struct timespec));
 		knet_h->pingbuf->khp_ping_link = dst_link->link_id;
 
 		if (knet_h->crypto_instance) {
 			if (crypto_encrypt_and_sign(knet_h,
 						    (const unsigned char *)knet_h->pingbuf,
 						    outlen,
 						    knet_h->pingbuf_crypt,
 						    &outlen) < 0) {
 				log_debug(knet_h, KNET_SUB_HEARTBEAT, "Unable to crypto ping packet");
 				return;
 			}
 
 			outbuf = knet_h->pingbuf_crypt;
 		}
 
 		len = sendto(dst_link->outsock, outbuf, outlen,
 			MSG_DONTWAIT | MSG_NOSIGNAL, (struct sockaddr *) &dst_link->dst_addr,
 			sizeof(struct sockaddr_storage));
 
 		dst_link->ping_last = clock_now;
 
 		if (len != outlen) {
 			log_debug(knet_h, KNET_SUB_HEARTBEAT,
 				  "Unable to send ping (sock: %d) packet (sendto): %d %s. recorded src ip: %s src port: %s dst ip: %s dst port: %s",
 				  dst_link->outsock, errno, strerror(errno),
 				  dst_link->status.src_ipaddr, dst_link->status.src_port,
 				  dst_link->status.dst_ipaddr, dst_link->status.dst_port);
 		} else {
 			dst_link->last_ping_size = outlen;
 		}
 	}
 
 	timespec_diff(pong_last, clock_now, &diff_ping);
 	if ((pong_last.tv_nsec) && 
 	    (diff_ping >= (dst_link->pong_timeout * 1000llu))) {
 		_link_down(knet_h, dst_host, dst_link);
 	}
 }
 
 void *_handle_heartbt_thread(void *data)
 {
 	knet_handle_t knet_h = (knet_handle_t) data;
 	struct knet_host *dst_host;
 	int link_idx;
 
 	/* preparing ping buffer */
 	knet_h->pingbuf->kh_version = KNET_HEADER_VERSION;
 	knet_h->pingbuf->kh_type = KNET_HEADER_TYPE_PING;
 	knet_h->pingbuf->kh_node = htons(knet_h->host_id);
 
 	while (!shutdown_in_progress(knet_h)) {
 		usleep(KNET_THREADS_TIMERES);
 
 		if (pthread_rwlock_rdlock(&knet_h->global_rwlock) != 0) {
 			log_debug(knet_h, KNET_SUB_HEARTBEAT, "Unable to get read lock");
 			continue;
 		}
 
 		for (dst_host = knet_h->host_head; dst_host != NULL; dst_host = dst_host->next) {
 			for (link_idx = 0; link_idx < KNET_MAX_LINK; link_idx++) {
 				if ((dst_host->link[link_idx].status.enabled != 1) ||
 				    ((dst_host->link[link_idx].dynamic == KNET_LINK_DYNIP) &&
 				     (dst_host->link[link_idx].status.dynconnected != 1)))
 					continue;
 				_handle_check_each(knet_h, dst_host, &dst_host->link[link_idx]);
 			}
 		}
 
 		pthread_rwlock_unlock(&knet_h->global_rwlock);
 	}
 
 	return NULL;
 }