Index: src/server/sv_client.c
===================================================================
--- src/server/sv_client.c	(revision 1043)
+++ src/server/sv_client.c	(working copy)
@@ -56,8 +56,13 @@
 	// see if we already have a challenge for this ip
 	challenge = &svs.challenges[0];
 	for (i = 0 ; i < MAX_CHALLENGES ; i++, challenge++) {
-		if ( !challenge->connected && NET_CompareAdr( from, challenge->adr ) ) {
-			break;
+		if ( NET_CompareAdr( from, challenge->adr ) ) {
+			if ( !challenge->connected )
+				break;
+			else if ( challenge->inuse ) {
+				NET_OutOfBandPrint( NS_SERVER, from, "challengeResponse %i", challenge->challenge );
+				return;
+			}
 		}
 		if ( challenge->time < oldestTime ) {
 			oldestTime = challenge->time;
@@ -74,6 +79,7 @@
 		challenge->firstTime = svs.time;
 		challenge->time = svs.time;
 		challenge->connected = qfalse;
+		challenge->inuse = qtrue;
 		i = oldest;
 	}
 
@@ -341,6 +347,7 @@
 	for (i = 0 ; i < MAX_CHALLENGES ; i++, challenge++) {
 		if ( NET_CompareAdr( drop->netchan.remoteAddress, challenge->adr ) ) {
 			challenge->connected = qfalse;
+			challenge->inuse = qfalse;
 			break;
 		}
 	}
Index: src/server/server.h
===================================================================
--- src/server/server.h	(revision 1043)
+++ src/server/server.h	(working copy)
@@ -189,6 +189,7 @@
 	int			pingTime;			// time the challenge response was sent to client
 	int			firstTime;			// time the adr was first used, for authorize timeout checks
 	qboolean	connected;
+	qboolean	inuse;
 } challenge_t;