diff -Nur busybox-1.1.1/include/usage.h busybox-1.1.1-owrt/include/usage.h
--- busybox-1.1.1/include/usage.h	2006-04-01 18:26:21.000000000 +0200
+++ busybox-1.1.1-owrt/include/usage.h	2006-04-01 18:27:45.000000000 +0200
@@ -3268,6 +3268,7 @@
 	"\t-n,\t--now\tExit with failure if lease cannot be immediately negotiated\n" \
 	"\t-p,\t--pidfile=file\tStore process ID of daemon in file\n" \
 	"\t-q,\t--quit\tQuit after obtaining lease\n" \
+	"\t-R,\t--release\tRelease IP on quit\n" \
 	"\t-r,\t--request=IP\tIP address to request (default: none)\n" \
 	"\t-s,\t--script=file\tRun file at dhcp events (default: /usr/share/udhcpc/default.script)\n" \
 	"\t-t,\t--retries=NUM\tSend up to NUM request packets\n"\
diff -Nur busybox-1.1.1/networking/udhcp/dhcpc.c busybox-1.1.1-owrt/networking/udhcp/dhcpc.c
--- busybox-1.1.1/networking/udhcp/dhcpc.c	2006-03-22 22:16:19.000000000 +0100
+++ busybox-1.1.1-owrt/networking/udhcp/dhcpc.c	2006-04-01 18:28:19.000000000 +0200
@@ -49,6 +49,7 @@
 	.abort_if_no_lease = 0,
 	.foreground = 0,
 	.quit_after_lease = 0,
+	.release_on_quit = 0,
 	.background_if_no_lease = 0,
 	.interface = "eth0",
 	.pidfile = NULL,
@@ -82,6 +83,7 @@
 "                                  immediately negotiated.\n"
 "  -p, --pidfile=file              Store process ID of daemon in file\n"
 "  -q, --quit                      Quit after obtaining lease\n"
+"  -R, --release                   Release IP on quit\n"
 "  -r, --request=IP                IP address to request (default: none)\n"
 "  -s, --script=file               Run file at dhcp events (default:\n"
 "                                  " DEFAULT_SCRIPT ")\n"
@@ -203,6 +205,7 @@
 		{"now",		no_argument,		0, 'n'},
 		{"pidfile",	required_argument,	0, 'p'},
 		{"quit",	no_argument,		0, 'q'},
+		{"release",	no_argument,		0, 'R'},
 		{"request",	required_argument,	0, 'r'},
 		{"script",	required_argument,	0, 's'},
 		{"timeout",	required_argument,	0, 'T'},
@@ -214,7 +217,7 @@
 	/* get options */
 	while (1) {
 		int option_index = 0;
-		c = getopt_long(argc, argv, "c:CV:fbH:h:F:i:np:qr:s:T:t:v", arg_options, &option_index);
+		c = getopt_long(argc, argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:v", arg_options, &option_index);
 		if (c == -1) break;
 
 		switch (c) {
@@ -284,6 +287,9 @@
 		case 'q':
 			client_config.quit_after_lease = 1;
 			break;
+		case 'R':
+			client_config.release_on_quit = 1;
+			break;
 		case 'r':
 			requested_ip = inet_addr(optarg);
 			break;
@@ -527,8 +533,11 @@
 
 					state = BOUND;
 					change_mode(LISTEN_NONE);
-					if (client_config.quit_after_lease)
+					if (client_config.quit_after_lease) {
+						if (client_config.release_on_quit)
+							perform_release();
 						return 0;
+					}
 					if (!client_config.foreground)
 						client_background();
 
@@ -553,12 +562,13 @@
 			case SIGUSR1:
 				perform_renew();
 				break;
-			case SIGUSR2:
-				perform_release();
-				break;
 			case SIGTERM:
 				LOG(LOG_INFO, "Received SIGTERM");
+				if (!client_config.release_on_quit)
 				return 0;
+			case SIGUSR2:
+				perform_release();
+				break;
 			}
 		} else if (retval == -1 && errno == EINTR) {
 			/* a signal was caught */
diff -Nur busybox-1.1.1/networking/udhcp/dhcpc.h busybox-1.1.1-owrt/networking/udhcp/dhcpc.h
--- busybox-1.1.1/networking/udhcp/dhcpc.h	2006-03-22 22:16:19.000000000 +0100
+++ busybox-1.1.1-owrt/networking/udhcp/dhcpc.h	2006-04-01 18:27:45.000000000 +0200
@@ -19,6 +19,7 @@
 struct client_config_t {
 	char foreground;		/* Do not fork */
 	char quit_after_lease;		/* Quit after obtaining lease */
+	char release_on_quit;		/* perform release on quit */
 	char abort_if_no_lease;		/* Abort if no lease */
 	char background_if_no_lease;	/* Fork to background if no lease */
 	char *interface;		/* The name of the interface to use */
