diff --git a/src/smblib/smbdefs.h b/src/smblib/smbdefs.h
index e9b6fb704adace190891d424130d75e12849f89d..0912b2a6dab6dde7ec6e42282d090d4049d3880b 100644
--- a/src/smblib/smbdefs.h
+++ b/src/smblib/smbdefs.h
@@ -182,7 +182,7 @@
 #define SENDER				0x00
 #define SENDERAGENT 		0x01
 #define SENDERNETTYPE		0x02
-#define SENDERNETADDR		0x03
+#define SENDERNETADDR		0x03		/* Note: SENDERNETTYPE may be NET_NONE and this field present and contain a valid string */
 #define SENDEREXT			0x04
 #define SENDERPOS			0x05
 #define SENDERORG			0x06
@@ -216,7 +216,7 @@
 #define RECIPIENT			0x30
 #define RECIPIENTAGENT		0x31
 #define RECIPIENTNETTYPE	0x32
-#define RECIPIENTNETADDR	0x33
+#define RECIPIENTNETADDR	0x33	/* Note: RECIPIENTNETTYPE may be NET_NONE and this field present and contain a valid string */
 #define RECIPIENTEXT		0x34
 #define RECIPIENTPOS		0x35
 #define RECIPIENTORG		0x36