diff -aur ipsec-tools-0.4-orig/src/racoon/isakmp_agg.c ipsec-tools-0.4/src/racoon/isakmp_agg.c
--- ipsec-tools-0.4-orig/src/racoon/isakmp_agg.c	2004-03-23 04:50:27.000000000 -0800
+++ ipsec-tools-0.4/src/racoon/isakmp_agg.c	2005-12-03 11:25:10.000000000 -0800
@@ -400,7 +400,11 @@
 	}
 
 	/* payload existency check */
-	/* XXX to be checked each authentication method. */
+	if (iph1->dhpub_p == NULL || iph1->nonce_p == NULL) {
+		plog(LLV_ERROR, LOCATION, iph1->remote,
+			"few isakmp message received.\n");
+		goto end;
+	}
 
 	/* verify identifier */
 	if (ipsecdoi_checkid1(iph1) != 0) {
@@ -755,7 +759,11 @@
 	}
 
 	/* payload existency check */
-	/* XXX to be checked each authentication method. */
+	if (iph1->dhpub_p == NULL || iph1->nonce_p == NULL) {
+		plog(LLV_ERROR, LOCATION, iph1->remote,
+			"few isakmp message received.\n");
+		goto end;
+	}
 
 	/* verify identifier */
 	if (ipsecdoi_checkid1(iph1) != 0) {