- 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/client/client.h

@@ -260,6 +260,10 @@ typedef struct {
 	float voipPower;
 #endif
 
+#ifdef PROTOCOL_SUPPORT_OLD
+	qboolean compat;
+#endif
+
 	// big stuff at end of structure so most offsets are 15 bits or less
 	netchan_t	netchan;
 } clientConnection_t;