- Harden the client and server protocol against UDP spoofing attacks. This will defend ioquake3 against http://aluigi.altervista.org/papers/q3noclient.txt (#3041)

- Retains full compatibility to the old but unsecure protocol between clients and servers
- Harden the connection process against DoS attacks, possibly connected to UDP spoofing

code/qcommon/files.c

@@ -1030,6 +1030,11 @@ qboolean FS_IsDemoExt(const char *filename, int namelen)
 		if(protocol == com_protocol->integer)
 			return qtrue;
 
+#ifdef PROTOCOL_SUPPORT_OLD
+                if(protocol == PROTOCOL_OLD_VERSION)
+                        return qtrue;
+#endif
+
 		for(index = 0; demo_protocols[index]; index++)
 		{
 			if(demo_protocols[index] == protocol)