diff --git a/libtransmission/natpmp.c b/libtransmission/natpmp.c
index d205eabbd..ff487c864 100644
--- a/libtransmission/natpmp.c
+++ b/libtransmission/natpmp.c
@@ -167,11 +167,14 @@ tr_natpmpPulse( struct tr_natpmp * nat,
         logVal( "readnatpmpresponseorretry", val );
         if( val >= 0 )
         {
-            tr_ninf( getKey( ), _(
-                         "no longer forwarding port %d" ), nat->port );
-            nat->state = TR_NATPMP_IDLE;
-            nat->port = -1;
-            nat->isMapped = 0;
+            const int port = resp.pnu.newportmapping.privateport;
+            tr_ninf( getKey( ), _( "no longer forwarding port %d" ), port );
+            if( nat->port == port )
+            {
+                nat->port = -1;
+                nat->state = TR_NATPMP_IDLE;
+                nat->isMapped = 0;
+            }
         }
         else if( val != NATPMP_TRYAGAIN )
         {