diff --git a/source3/include/smb.h b/source3/include/smb.h
index 873657a..3189af0 100644
--- a/source3/include/smb.h
+++ b/source3/include/smb.h
@@ -1027,6 +1027,7 @@ struct bitmap {
 /* this is used on a TConX. I'm not sure the name is very helpful though */
 #define SMB_SUPPORT_SEARCH_BITS        0x0001
 #define SMB_SHARE_IN_DFS               0x0002
+#define SMB_EXTENDED_SIGNATURES        0x0020
 
 /* Named pipe write mode flags. Used in writeX calls. */
 #define PIPE_RAW_MODE 0x4
@@ -1289,6 +1290,7 @@ char *strdup(char *s);
 #define FLAGS2_WIN2K_SIGNATURE         0xC852 /* Hack alert ! For now... JRA. */
 
 /* TCONX Flag (smb_vwv2). */
+#define TCONX_FLAG_EXTENDED_SIGNATURES  0x4
 #define TCONX_FLAG_EXTENDED_RESPONSE	0x8
 
 /* File Status Flags. See:
diff --git a/source3/smbd/reply.c b/source3/smbd/reply.c
index ac471aa..450cd8b 100644
--- a/source3/smbd/reply.c
+++ b/source3/smbd/reply.c
@@ -711,6 +711,7 @@ void reply_tcon_and_X(struct smb_request *req)
 	const char *p, *q;
 	uint16 tcon_flags;
 	struct smbd_server_connection *sconn = req->sconn;
+	uint16_t optional_support = 0
 
 	START_PROFILE(SMBtconX);
 
@@ -855,15 +856,21 @@ void reply_tcon_and_X(struct smb_request *req)
 
 		/* what does setting this bit do? It is set by NT4 and
 		   may affect the ability to autorun mounted cdroms */
-		SSVAL(req->outbuf, smb_vwv2, SMB_SUPPORT_SEARCH_BITS|
-		      (lp_csc_policy(SNUM(conn)) << 2));
+		optional_support |= SMB_SUPPORT_SEARCH_BITS;
+		optional_support |= (lp_csc_policy(SNUM(conn)) << 2);
 
 		if (lp_msdfs_root(SNUM(conn)) && lp_host_msdfs()) {
 			DEBUG(2,("Serving %s as a Dfs root\n",
 				 lp_servicename(SNUM(conn)) ));
-			SSVAL(req->outbuf, smb_vwv2,
-			      SMB_SHARE_IN_DFS | SVAL(req->outbuf, smb_vwv2));
+			optional_support |= SMB_SHARE_IN_DFS;
 		}
+
+		if (srv_is_signing_active(sconn) &&
+				(tcon_flags & TCONX_FLAG_EXTENDED_SIGNATURES)) {
+			optional_support |= SMB_EXTENDED_SIGNATURES;
+		}
+
+		SSVAL(req->outbuf, smb_vwv2, optional_support);
 	}