diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c
index 049368c91b56..49cc6f22cc5a 100644
--- a/sys/netinet/sctp_usrreq.c
+++ b/sys/netinet/sctp_usrreq.c
@@ -5327,6 +5327,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 				return (EINVAL);
 			}
 			if ((paddrp->spp_flags & SPP_PMTUD_DISABLE) &&
+			    (paddrp->spp_pathmtu > 0) &&
 			    ((paddrp->spp_pathmtu < SCTP_SMALLEST_PMTU) ||
 			    (paddrp->spp_pathmtu > SCTP_LARGEST_PMTU))) {
 				if (stcb)
@@ -5371,23 +5372,25 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 							    SCTP_FROM_SCTP_USRREQ + SCTP_LOC_11);
 						}
 						net->dest_state |= SCTP_ADDR_NO_PMTUD;
-						net->mtu = paddrp->spp_pathmtu;
-						switch (net->ro._l_addr.sa.sa_family) {
+						if (paddrp->spp_pathmtu > 0) {
+							net->mtu = paddrp->spp_pathmtu;
+							switch (net->ro._l_addr.sa.sa_family) {
 #ifdef INET
-						case AF_INET:
-							net->mtu += SCTP_MIN_V4_OVERHEAD;
-							break;
+							case AF_INET:
+								net->mtu += SCTP_MIN_V4_OVERHEAD;
+								break;
 #endif
 #ifdef INET6
-						case AF_INET6:
-							net->mtu += SCTP_MIN_OVERHEAD;
-							break;
+							case AF_INET6:
+								net->mtu += SCTP_MIN_OVERHEAD;
+								break;
 #endif
-						default:
-							break;
-						}
-						if (net->mtu < stcb->asoc.smallest_mtu) {
-							sctp_pathmtu_adjustment(stcb, net->mtu);
+							default:
+								break;
+							}
+							if (net->mtu < stcb->asoc.smallest_mtu) {
+								sctp_pathmtu_adjustment(stcb, net->mtu);
+							}
 						}
 					}
 					if (paddrp->spp_flags & SPP_PMTUD_ENABLE) {
@@ -5396,7 +5399,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 						}
 						net->dest_state &= ~SCTP_ADDR_NO_PMTUD;
 					}
-					if (paddrp->spp_pathmaxrxt) {
+					if (paddrp->spp_pathmaxrxt > 0) {
 						if (net->dest_state & SCTP_ADDR_PF) {
 							if (net->error_count > paddrp->spp_pathmaxrxt) {
 								net->dest_state &= ~SCTP_ADDR_PF;
@@ -5439,7 +5442,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 #endif
 				} else {
 					/************************ASSOC ONLY -- NO NET SPECIFIC SET ******************/
-					if (paddrp->spp_pathmaxrxt != 0) {
+					if (paddrp->spp_pathmaxrxt > 0) {
 						stcb->asoc.def_net_failure = paddrp->spp_pathmaxrxt;
 						TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 							if (net->dest_state & SCTP_ADDR_PF) {
@@ -5471,7 +5474,6 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 							net->failure_threshold = paddrp->spp_pathmaxrxt;
 						}
 					}
-
 					if (paddrp->spp_flags & SPP_HB_ENABLE) {
 						if (paddrp->spp_hbinterval != 0) {
 							stcb->asoc.heart_beat_delay = paddrp->spp_hbinterval;
@@ -5514,26 +5516,30 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 								    SCTP_FROM_SCTP_USRREQ + SCTP_LOC_16);
 							}
 							net->dest_state |= SCTP_ADDR_NO_PMTUD;
-							net->mtu = paddrp->spp_pathmtu;
-							switch (net->ro._l_addr.sa.sa_family) {
+							if (paddrp->spp_pathmtu > 0) {
+								net->mtu = paddrp->spp_pathmtu;
+								switch (net->ro._l_addr.sa.sa_family) {
 #ifdef INET
-							case AF_INET:
-								net->mtu += SCTP_MIN_V4_OVERHEAD;
-								break;
+								case AF_INET:
+									net->mtu += SCTP_MIN_V4_OVERHEAD;
+									break;
 #endif
 #ifdef INET6
-							case AF_INET6:
-								net->mtu += SCTP_MIN_OVERHEAD;
-								break;
+								case AF_INET6:
+									net->mtu += SCTP_MIN_OVERHEAD;
+									break;
 #endif
-							default:
-								break;
-							}
-							if (net->mtu < stcb->asoc.smallest_mtu) {
-								sctp_pathmtu_adjustment(stcb, net->mtu);
+								default:
+									break;
+								}
+								if (net->mtu < stcb->asoc.smallest_mtu) {
+									sctp_pathmtu_adjustment(stcb, net->mtu);
+								}
 							}
 						}
-						stcb->asoc.default_mtu = paddrp->spp_pathmtu;
+						if (paddrp->spp_pathmtu > 0) {
+							stcb->asoc.default_mtu = paddrp->spp_pathmtu;
+						}
 						sctp_stcb_feature_on(inp, stcb, SCTP_PCB_FLAGS_DO_NOT_PMTUD);
 					}
 					if (paddrp->spp_flags & SPP_PMTUD_ENABLE) {
@@ -5580,7 +5586,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 					 * set it with the options on the
 					 * socket
 					 */
-					if (paddrp->spp_pathmaxrxt != 0) {
+					if (paddrp->spp_pathmaxrxt > 0) {
 						inp->sctp_ep.def_net_failure = paddrp->spp_pathmaxrxt;
 					}
 
@@ -5606,7 +5612,9 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 						inp->sctp_ep.default_mtu = 0;
 						sctp_feature_off(inp, SCTP_PCB_FLAGS_DO_NOT_PMTUD);
 					} else if (paddrp->spp_flags & SPP_PMTUD_DISABLE) {
-						inp->sctp_ep.default_mtu = paddrp->spp_pathmtu;
+						if (paddrp->spp_pathmtu > 0) {
+							inp->sctp_ep.default_mtu = paddrp->spp_pathmtu;
+						}
 						sctp_feature_on(inp, SCTP_PCB_FLAGS_DO_NOT_PMTUD);
 					}
 					if (paddrp->spp_flags & SPP_DSCP) {