diff --git a/bin/named/include/named/zoneconf.h b/bin/named/include/named/zoneconf.h
index 2286b09fa6..b07ea82d03 100644
--- a/bin/named/include/named/zoneconf.h
+++ b/bin/named/include/named/zoneconf.h
@@ -31,12 +31,14 @@
  * table in 'cctx'.
  */
 
-isc_result_t dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx,
-				dns_aclconfctx_t *ac,
+isc_result_t dns_zone_configure(dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 				dns_c_zone_t *czone, dns_zone_t *zone);
 /*
- *	Configure or reconfigure a zone according to the named.conf
- *      data in 'ctx' and 'czone'.
+ * Configure or reconfigure a zone according to the named.conf
+ * data in 'ctx' and 'czone'.
+ *
+ * The zone origin is not configured, it is assumed to have been set
+ * at zone creation time.
  *
  * Require:
  *	'lctx' to be initalised or NULL.
@@ -46,6 +48,14 @@ isc_result_t dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx,
  *	'zone' to be initalised.
  */
 
+isc_boolean_t
+dns_zone_reusable(dns_zone_t *zone, dns_c_zone_t *czone);
+/*
+ * If 'zone' can be safely reconfigured according to the configuration
+ * data in 'czone', return ISC_TRUE.  If the configuration data is so
+ * different from the current zone state that the zone needs to be destroyed
+ * and recreated, return ISC_FALSE.
+ */
 
 ISC_LANG_ENDDECLS
 
diff --git a/bin/named/zoneconf.c b/bin/named/zoneconf.c
index 17335f9f4e..004a4740eb 100644
--- a/bin/named/zoneconf.c
+++ b/bin/named/zoneconf.c
@@ -61,8 +61,27 @@ configure_zone_acl(dns_c_zone_t *czone, dns_c_ctx_t *cctx,
 	}
 }
 
+
+static dns_zonetype_t
+dns_zonetype_fromconf(dns_c_zonetype_t cztype) {
+	switch (cztype) {
+	case dns_c_zone_master:
+		return dns_zone_master;
+	case dns_c_zone_forward:
+		return dns_zone_forward;
+	case dns_c_zone_slave:
+		return dns_zone_slave;
+	case dns_c_zone_stub:
+		return dns_zone_stub;
+	case dns_c_zone_hint:
+		return dns_zone_hint;
+	}
+	INSIST(0);
+	return (dns_zone_none); /*NOTREACHED*/
+}
+
 isc_result_t
-dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
+dns_zone_configure(dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 		   dns_c_zone_t *czone, dns_zone_t *zone)
 {
 	isc_result_t result;
@@ -77,24 +96,11 @@ dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 	isc_int32_t maxxfr;
 	isc_int32_t idle;
 	in_port_t port;
-	const char *origin;
 	isc_sockaddr_t sockaddr_any;
 
-	ctx = ctx;	/* unused */
-	lctx = lctx;	/* XXX unused */
-
 	isc_sockaddr_fromin6(&sockaddr_any, &in6addr_any, 0);
 	dns_zone_setclass(zone, czone->zclass);
 
-	origin = NULL;
-	result = dns_c_zone_getname(czone, &origin);
-	if (result != DNS_R_SUCCESS)
-		return (result);
-	/* XXX casting away const */
-	result = dns_zone_setorigin(zone, (char *) origin);
-	if (result != DNS_R_SUCCESS)
-		return (result);
-
 	/* XXX needs to be an zone option */
 	result = dns_zone_setdbtype(zone, "rbt");
 	if (result != DNS_R_SUCCESS)
@@ -414,3 +420,24 @@ dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 	return (DNS_R_SUCCESS);
 }
 
+isc_boolean_t
+dns_zone_reusable(dns_zone_t *zone, dns_c_zone_t *czone)
+{
+	const char *cfilename;
+	const char *zfilename;
+
+	if (dns_zonetype_fromconf(czone->ztype) != dns_zone_gettype(zone))
+		return (ISC_FALSE);
+
+	cfilename = NULL;
+	(void) dns_c_zone_getfile(czone, &cfilename);
+	zfilename = dns_zone_getdatabase(zone);
+	if (cfilename == NULL || zfilename == NULL ||
+	    strcmp(cfilename, zfilename) != 0)
+		return (ISC_FALSE);
+
+	/* XXX Compare masters, too. */
+
+	return (ISC_TRUE);
+}
+	
diff --git a/lib/dns/include/dns/zoneconf.h b/lib/dns/include/dns/zoneconf.h
index 2286b09fa6..b07ea82d03 100644
--- a/lib/dns/include/dns/zoneconf.h
+++ b/lib/dns/include/dns/zoneconf.h
@@ -31,12 +31,14 @@
  * table in 'cctx'.
  */
 
-isc_result_t dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx,
-				dns_aclconfctx_t *ac,
+isc_result_t dns_zone_configure(dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 				dns_c_zone_t *czone, dns_zone_t *zone);
 /*
- *	Configure or reconfigure a zone according to the named.conf
- *      data in 'ctx' and 'czone'.
+ * Configure or reconfigure a zone according to the named.conf
+ * data in 'ctx' and 'czone'.
+ *
+ * The zone origin is not configured, it is assumed to have been set
+ * at zone creation time.
  *
  * Require:
  *	'lctx' to be initalised or NULL.
@@ -46,6 +48,14 @@ isc_result_t dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx,
  *	'zone' to be initalised.
  */
 
+isc_boolean_t
+dns_zone_reusable(dns_zone_t *zone, dns_c_zone_t *czone);
+/*
+ * If 'zone' can be safely reconfigured according to the configuration
+ * data in 'czone', return ISC_TRUE.  If the configuration data is so
+ * different from the current zone state that the zone needs to be destroyed
+ * and recreated, return ISC_FALSE.
+ */
 
 ISC_LANG_ENDDECLS
 
diff --git a/lib/dns/zoneconf.c b/lib/dns/zoneconf.c
index 17335f9f4e..004a4740eb 100644
--- a/lib/dns/zoneconf.c
+++ b/lib/dns/zoneconf.c
@@ -61,8 +61,27 @@ configure_zone_acl(dns_c_zone_t *czone, dns_c_ctx_t *cctx,
 	}
 }
 
+
+static dns_zonetype_t
+dns_zonetype_fromconf(dns_c_zonetype_t cztype) {
+	switch (cztype) {
+	case dns_c_zone_master:
+		return dns_zone_master;
+	case dns_c_zone_forward:
+		return dns_zone_forward;
+	case dns_c_zone_slave:
+		return dns_zone_slave;
+	case dns_c_zone_stub:
+		return dns_zone_stub;
+	case dns_c_zone_hint:
+		return dns_zone_hint;
+	}
+	INSIST(0);
+	return (dns_zone_none); /*NOTREACHED*/
+}
+
 isc_result_t
-dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
+dns_zone_configure(dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 		   dns_c_zone_t *czone, dns_zone_t *zone)
 {
 	isc_result_t result;
@@ -77,24 +96,11 @@ dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 	isc_int32_t maxxfr;
 	isc_int32_t idle;
 	in_port_t port;
-	const char *origin;
 	isc_sockaddr_t sockaddr_any;
 
-	ctx = ctx;	/* unused */
-	lctx = lctx;	/* XXX unused */
-
 	isc_sockaddr_fromin6(&sockaddr_any, &in6addr_any, 0);
 	dns_zone_setclass(zone, czone->zclass);
 
-	origin = NULL;
-	result = dns_c_zone_getname(czone, &origin);
-	if (result != DNS_R_SUCCESS)
-		return (result);
-	/* XXX casting away const */
-	result = dns_zone_setorigin(zone, (char *) origin);
-	if (result != DNS_R_SUCCESS)
-		return (result);
-
 	/* XXX needs to be an zone option */
 	result = dns_zone_setdbtype(zone, "rbt");
 	if (result != DNS_R_SUCCESS)
@@ -414,3 +420,24 @@ dns_zone_configure(isc_log_t *lctx, dns_c_ctx_t *ctx, dns_aclconfctx_t *ac,
 	return (DNS_R_SUCCESS);
 }
 
+isc_boolean_t
+dns_zone_reusable(dns_zone_t *zone, dns_c_zone_t *czone)
+{
+	const char *cfilename;
+	const char *zfilename;
+
+	if (dns_zonetype_fromconf(czone->ztype) != dns_zone_gettype(zone))
+		return (ISC_FALSE);
+
+	cfilename = NULL;
+	(void) dns_c_zone_getfile(czone, &cfilename);
+	zfilename = dns_zone_getdatabase(zone);
+	if (cfilename == NULL || zfilename == NULL ||
+	    strcmp(cfilename, zfilename) != 0)
+		return (ISC_FALSE);
+
+	/* XXX Compare masters, too. */
+
+	return (ISC_TRUE);
+}
+