Index: smbd/reply.c
===================================================================
--- smbd/reply.c	(revision 1835)
+++ smbd/reply.c	(working copy)
@@ -1735,7 +1735,7 @@
 	 * reply_readbraw has already checked the length.
 	 */
 
-	if ((nread > 0) && (lp_write_cache_size(SNUM(conn)) == 0) && lp_use_sendfile(SNUM(conn)) ) {
+	if (chain_size ==0 && (nread > 0) && (lp_write_cache_size(SNUM(conn)) == 0) && lp_use_sendfile(SNUM(conn)) ) {
 		DATA_BLOB header;
 
 		_smb_setlen(outbuf,nread);
@@ -2075,7 +2075,7 @@
 	 * on a train in Germany :-). JRA.
 	 */
 
-	if ((CVAL(inbuf,smb_vwv0) == 0xFF) && lp_use_sendfile(SNUM(conn)) &&
+	if (chain_size ==0 && (CVAL(inbuf,smb_vwv0) == 0xFF) && lp_use_sendfile(SNUM(conn)) &&
 			(lp_write_cache_size(SNUM(conn)) == 0) ) {
 		SMB_STRUCT_STAT sbuf;
 		DATA_BLOB header;
Index: param/loadparm.c
===================================================================
--- param/loadparm.c	(revision 1835)
+++ param/loadparm.c	(working copy)
@@ -4320,6 +4320,11 @@
 
 BOOL lp_use_sendfile(int snum)
 {
+	extern int Protocol;
+	/* Using sendfile blows the brains out of any DOS or Win9x TCP stack... JRA. */
+	if (Protocol < PROTOCOL_NT1) {
+		return False;
+	}
 	return (_lp_use_sendfile(snum) && (get_remote_arch() != RA_WIN95) && !srv_is_signing_active());
 }