diff --git a/nbss/nbss.go b/nbss/nbss.go
index 0baac68..bb92924 100644
--- a/nbss/nbss.go
+++ b/nbss/nbss.go
@@ -67,7 +67,9 @@ func (t *NBSSMatcher) Match(info osm.MatchInfo, index int, packet *osm.Packet) e
 		return osm.NotMatchedError()
 	}
 
-	if NBSS_NEGATIVE_SESSION_RESPONSE != n.MsgType {
+	switch n.MsgType {
+	case NBSS_POSITIVE_SESSION_RESPONSE, NBSS_NEGATIVE_SESSION_RESPONSE:
+	default:
 		return osm.NotMatchedError()
 	}