diff -up dhcp-4.2.4b1/client/dhclient.c.send_release dhcp-4.2.4b1/client/dhclient.c
--- dhcp-4.2.4b1/client/dhclient.c.send_release	2012-04-16 17:48:52.000000000 +0200
+++ dhcp-4.2.4b1/client/dhclient.c	2012-04-16 17:50:44.357396720 +0200
@@ -2764,8 +2764,8 @@ void send_release (cpp)
 	      inet_ntoa (destination.sin_addr),
 	      ntohs (destination.sin_port), client -> xid);
 
-	if (fallback_interface) {
-		result = send_packet(fallback_interface, NULL, &client->packet,
+	if (client -> interface) {
+		result = send_packet(client -> interface, NULL, &client->packet,
 				      client->packet_length, from, &destination,
 				      NULL);
 		if (result < 0) {
@@ -2776,7 +2776,7 @@ void send_release (cpp)
 		}
         } else {
 		/* Send out a packet. */
-		result = send_packet(client->interface, NULL, &client->packet,
+		result = send_packet(fallback_interface, NULL, &client->packet,
 				      client->packet_length, from, &destination,
 				      NULL);
 		if (result < 0) {