diff --git a/CHANGES b/CHANGES
index ae5945b4a8..1ce035673d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+2285.	[func]		Test framework for client memory context management.
+			[RT #17377]
+
 2284.	[bug]		Memory leak in UPDATE prerequisite processing.
 			[RT #17377]
 
diff --git a/bin/named/client.c b/bin/named/client.c
index df98201cc8..b209af1068 100644
--- a/bin/named/client.c
+++ b/bin/named/client.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: client.c,v 1.250 2007/11/26 04:47:17 marka Exp $ */
+/* $Id: client.c,v 1.251 2008/01/02 05:03:07 marka Exp $ */
 
 #include <config.h>
 
@@ -463,6 +463,8 @@ exit_check(ns_client_t *client) {
 
 		if (client->state == client->newstate) {
 			client->newstate = NS_CLIENTSTATE_MAX;
+			if (client->needshutdown)
+				isc_task_shutdown(client->task);
 			goto unlock;
 		}
 	}
@@ -519,6 +521,14 @@ exit_check(ns_client_t *client) {
 
 		CTRACE("free");
 		client->magic = 0;
+		/*
+		 * Check that there are no other external references to
+		 * the memory context.
+		 */
+		if (ns_g_clienttest && isc_mem_references(client->mctx) != 1) {
+			isc_mem_stats(client->mctx, stderr);
+			INSIST(0);
+		}
 		isc_mem_putanddetach(&client->mctx, client, sizeof(*client));
 
 		goto unlock;
@@ -592,6 +602,7 @@ client_shutdown(isc_task_t *task, isc_event_t *event) {
 	}
 
 	client->newstate = NS_CLIENTSTATE_FREED;
+	client->needshutdown = ISC_FALSE;
 	(void)exit_check(client);
 }
 
@@ -644,7 +655,7 @@ ns_client_checkactive(ns_client_t *client) {
 		 * keep it active to make up for the shortage.
 		 */
 		isc_boolean_t need_another_client = ISC_FALSE;
-		if (TCP_CLIENT(client)) {
+		if (TCP_CLIENT(client) && !ns_g_clienttest) {
 			LOCK(&client->interface->lock);
 			if (client->interface->ntcpcurrent <
 			    client->interface->ntcptarget)
@@ -1844,6 +1855,8 @@ get_clientmctx(ns_clientmgr_t *manager, isc_mem_t **mctxp) {
 	/*
 	 * Caller must be holding the manager lock.
 	 */
+	if (ns_g_clienttest)
+		return (isc_mem_create(0, 0, mctxp));
 #if NMCTXS > 0
 	INSIST(manager->nextmctx < NMCTXS);
 	clientmctx = manager->mctxpool[manager->nextmctx];
@@ -1999,6 +2012,8 @@ client_create(ns_clientmgr_t *manager, ns_client_t **clientp) {
 	if (result != ISC_R_SUCCESS)
 		goto cleanup_query;
 
+	client->needshutdown = ns_g_clienttest;
+
 	CTRACE("create");
 
 	*clientp = client;
@@ -2420,7 +2435,9 @@ ns_clientmgr_createclients(ns_clientmgr_t *manager, unsigned int n,
 		 * Allocate a client.  First try to get a recycled one;
 		 * if that fails, make a new one.
 		 */
-		client = ISC_LIST_HEAD(manager->inactive);
+		client = NULL;
+		if (!ns_g_clienttest)
+			client = ISC_LIST_HEAD(manager->inactive);
 		if (client != NULL) {
 			MTRACE("recycle");
 			ISC_LIST_UNLINK(manager->inactive, client, link);
diff --git a/bin/named/include/named/client.h b/bin/named/include/named/client.h
index 44c800d174..8316930fbe 100644
--- a/bin/named/include/named/client.h
+++ b/bin/named/include/named/client.h
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: client.h,v 1.82 2007/06/18 23:47:19 tbox Exp $ */
+/* $Id: client.h,v 1.83 2008/01/02 05:03:07 marka Exp $ */
 
 #ifndef NAMED_CLIENT_H
 #define NAMED_CLIENT_H 1
@@ -97,6 +97,13 @@ struct ns_client {
 	int			nupdates;
 	int			nctls;
 	int			references;
+	isc_boolean_t		needshutdown; 	/*
+						 * Used by clienttest to get
+						 * the client to go from
+						 * inactive to free state
+						 * by shutting down the
+						 * client's task.
+						 */
 	unsigned int		attributes;
 	isc_task_t *		task;
 	dns_view_t *		view;
diff --git a/bin/named/include/named/globals.h b/bin/named/include/named/globals.h
index de0c084fb3..3adef247a8 100644
--- a/bin/named/include/named/globals.h
+++ b/bin/named/include/named/globals.h
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: globals.h,v 1.73 2007/09/26 03:22:43 marka Exp $ */
+/* $Id: globals.h,v 1.74 2008/01/02 05:03:07 marka Exp $ */
 
 #ifndef NAMED_GLOBALS_H
 #define NAMED_GLOBALS_H 1
@@ -115,6 +115,7 @@ EXTERN const char *		ns_g_username		INIT(NULL);
 EXTERN int			ns_g_listen		INIT(3);
 EXTERN isc_time_t		ns_g_boottime;
 EXTERN isc_boolean_t		ns_g_memstatistics	INIT(ISC_FALSE);
+EXTERN isc_boolean_t		ns_g_clienttest		INIT(ISC_FALSE);
 
 #undef EXTERN
 #undef INIT
diff --git a/bin/named/main.c b/bin/named/main.c
index f2a3e74a8c..e943f620b0 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: main.c,v 1.158 2007/09/26 03:22:43 marka Exp $ */
+/* $Id: main.c,v 1.159 2008/01/02 05:03:07 marka Exp $ */
 
 /*! \file */
 
@@ -356,7 +356,7 @@ parse_command_line(int argc, char *argv[]) {
 
 	isc_commandline_errprint = ISC_FALSE;
 	while ((ch = isc_commandline_parse(argc, argv,
-			           "46c:C:d:fgi:lm:n:N:p:P:st:u:vx:")) != -1) {
+			         "46c:C:d:fgi:lm:n:N:p:P:st:T:u:vx:")) != -1) {
 		switch (ch) {
 		case '4':
 			if (disable4)
@@ -439,6 +439,17 @@ parse_command_line(int argc, char *argv[]) {
 			/* XXXJAB should we make a copy? */
 			ns_g_chrootdir = isc_commandline_argument;
 			break;
+		case 'T':
+			/*
+			 * clienttest: make clients single shot with their
+			 * 	       own memory context.
+			 */
+			if (strcmp(isc_commandline_argument, "clienttest") == 0)
+				ns_g_clienttest = ISC_TRUE;
+			else
+				fprintf(stderr, "unknown -T flag '%s\n",
+					isc_commandline_argument);
+			break;
 		case 'u':
 			ns_g_username = isc_commandline_argument;
 			break;
diff --git a/bin/named/query.c b/bin/named/query.c
index 29b113ad78..23c6bae576 100644
--- a/bin/named/query.c
+++ b/bin/named/query.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: query.c,v 1.298 2007/09/26 03:04:45 each Exp $ */
+/* $Id: query.c,v 1.299 2008/01/02 05:03:07 marka Exp $ */
 
 /*! \file */
 
@@ -4445,6 +4445,12 @@ ns_query_start(ns_client_t *client) {
 
 	CTRACE("ns_query_start");
 
+	/*
+	 * Test only.
+	 */
+	if (ns_g_clienttest && (client->attributes & NS_CLIENTATTR_TCP) == 0)
+		RUNTIME_CHECK(ns_client_replace(client) == ISC_R_SUCCESS);
+
 	/*
 	 * Ensure that appropriate cleanups occur.
 	 */
diff --git a/bin/tests/system/start.pl b/bin/tests/system/start.pl
index b22f74ce62..a681655ba0 100644
--- a/bin/tests/system/start.pl
+++ b/bin/tests/system/start.pl
@@ -15,7 +15,7 @@
 # OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 # PERFORMANCE OF THIS SOFTWARE.
 
-# $Id: start.pl,v 1.11 2007/06/19 23:47:00 tbox Exp $
+# $Id: start.pl,v 1.12 2008/01/02 05:03:07 marka Exp $
 
 # Framework for starting test servers.
 # Based on the type of server specified, check for port availability, remove
@@ -129,7 +129,9 @@ sub start_server {
 		if ($options) {
 			$command .= "$options";
 		} else {
-			$command .= "-m record,size,mctx -c named.conf -d 99 -g";
+			$command .= "-m record,size,mctx ";
+			$command .= "-T clienttest ";
+			$command .= "-c named.conf -d 99 -g";
 		}
 		$command .= " >named.run 2>&1 &";
 		$pid_file = "named.pid";
@@ -139,7 +141,10 @@ sub start_server {
 		if ($options) {
 			$command .= "$options";
 		} else {
-			$command .= "-m record,size,mctx -C resolv.conf -d 99 -g -i lwresd.pid -P 9210 -p 5300";
+			$command .= "-m record,size,mctx ";
+			$command .= "-T clienttest ";
+			$command .= "-C resolv.conf -d 99 -g ";
+			$command .= "-i lwresd.pid -P 9210 -p 5300";
 		}
 		$command .= " >lwresd.run 2>&1 &";
 		$pid_file = "lwresd.pid";
diff --git a/lib/isc/include/isc/mem.h b/lib/isc/include/isc/mem.h
index ade0794a32..1ccfc5e6f5 100644
--- a/lib/isc/include/isc/mem.h
+++ b/lib/isc/include/isc/mem.h
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: mem.h,v 1.72 2007/06/18 23:47:44 tbox Exp $ */
+/* $Id: mem.h,v 1.73 2008/01/02 05:03:07 marka Exp $ */
 
 #ifndef ISC_MEM_H
 #define ISC_MEM_H 1
@@ -377,6 +377,12 @@ isc_mem_checkdestroyed(FILE *file);
  * Fatally fails if there are still active contexts.
  */
 
+unsigned int
+isc_mem_references(isc_mem_t *ctx);
+/*%<
+ * Return the current reference count.
+ */
+
 /*
  * Memory pools
  */
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index 36b9a7b034..9ecb1eda9d 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: mem.c,v 1.137 2007/11/26 04:27:19 marka Exp $ */
+/* $Id: mem.c,v 1.138 2008/01/02 05:03:07 marka Exp $ */
 
 /*! \file */
 
@@ -1955,6 +1955,18 @@ isc_mem_checkdestroyed(FILE *file) {
 	UNLOCK(&lock);
 }
 
+unsigned int
+isc_mem_references(isc_mem_t *ctx) {
+	unsigned int references;
+	REQUIRE(VALID_CONTEXT(ctx));
+
+	MCTXLOCK(ctx, &ctx->lock);
+	references = ctx->references;
+	MCTXUNLOCK(ctx, &ctx->lock);
+
+	return (references);
+}
+
 #ifdef HAVE_LIBXML2
 
 void