diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 1276a44..5cc9636 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -330,7 +330,8 @@
 
 	while (dptr <= limit) {
 		if ((strncmp(dptr, hnfo->lname, hnfo->lnlen) != 0) &&
-		    (strncmp(dptr, hnfo->sname, hnfo->snlen) != 0)) {
+		    (hnfo->sname == NULL ||
+		     strncmp(dptr, hnfo->sname, hnfo->snlen) != 0)) {
 			dptr++;
 			continue;
 		}