diff --git a/bin/named/interfacemgr.c b/bin/named/interfacemgr.c
index b405de55ee..ac0479f4d5 100644
--- a/bin/named/interfacemgr.c
+++ b/bin/named/interfacemgr.c
@@ -150,7 +150,8 @@ ns_interface_create(ns_interfacemgr_t *mgr, isc_sockaddr_t *addr,
 	 */
 	ifp->udpdispatch = NULL;
 	result = dns_dispatch_create(mgr->mctx, ifp->udpsocket, ifp->task,
-				     4096, 50, 50, 17, 19, &ifp->udpdispatch);
+				     4096, 50, 50, 17, 19, NULL,
+				     &ifp->udpdispatch);
 	if (result != ISC_R_SUCCESS) {
 		UNEXPECTED_ERROR(__FILE__, __LINE__,
 				 "UDP dns_dispatch_create(): %s",
diff --git a/bin/tests/dispatch_tcp_test.c b/bin/tests/dispatch_tcp_test.c
index 03a78c0d94..8be667023a 100644
--- a/bin/tests/dispatch_tcp_test.c
+++ b/bin/tests/dispatch_tcp_test.c
@@ -107,7 +107,7 @@ my_accept(isc_task_t *task, isc_event_t *ev_in)
 	 */
 	disp = NULL;
 	RUNTIME_CHECK(dns_dispatch_create(mctx, ev->newsocket, task,
-					  512, 6, 1024, 17, 19, &disp)
+					  512, 6, 1024, 17, 19, NULL, &disp)
 		      == ISC_R_SUCCESS);
 
 	resp = NULL;
diff --git a/bin/tests/dispatch_test.c b/bin/tests/dispatch_test.c
index 6a2d1be625..f84dd74413 100644
--- a/bin/tests/dispatch_test.c
+++ b/bin/tests/dispatch_test.c
@@ -405,7 +405,8 @@ main(int argc, char *argv[])
 	 */
 	disp = NULL;
 	RUNTIME_CHECK(dns_dispatch_create(mctx, s0, t0, 512, 6, 1024,
-					 17, 19, &disp) == ISC_R_SUCCESS);
+					 17, 19, NULL, &disp)
+		      == ISC_R_SUCCESS);
 
 	RUNTIME_CHECK(isc_mutex_init(&client_lock) == ISC_R_SUCCESS);
 	RUNTIME_CHECK(isc_mutex_lock(&client_lock) == ISC_R_SUCCESS);
diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c
index a350ad9ef7..4962ed6767 100644
--- a/lib/dns/dispatch.c
+++ b/lib/dns/dispatch.c
@@ -45,7 +45,7 @@
 
 struct dns_dispentry {
 	unsigned int			magic;
-	dns_messageid_t			id;
+	isc_uint32_t			id;
 	unsigned int			bucket;
 	isc_sockaddr_t			host;
 	isc_task_t		       *task;
@@ -87,6 +87,7 @@ struct dns_dispatch {
 	ISC_LIST(dns_dispentry_t) rq_handlers;	/* request handler list */
 	ISC_LIST(dns_dispatchevent_t) rq_events; /* holder for rq events */
 	dns_tcpmsg_t		tcpmsg;		/* for tcp streams */
+	dns_dispatchmethods_t	methods;	/* methods to use */
 	isc_lfsr_t		qid_lfsr1;	/* state generator info */
 	isc_lfsr_t		qid_lfsr2;	/* state generator info */
 	unsigned int		qid_nbuckets;	/* hash table size */
@@ -112,8 +113,8 @@ static void destroy(dns_dispatch_t *);
 static void udp_recv(isc_task_t *, isc_event_t *);
 static void tcp_recv(isc_task_t *, isc_event_t *);
 static inline void startrecv(dns_dispatch_t *);
-static dns_messageid_t randomid(dns_dispatch_t *);
-static unsigned int hash(dns_dispatch_t *, isc_sockaddr_t *, dns_messageid_t);
+static isc_uint32_t dns_randomid(dns_dispatch_t *);
+static isc_uint32_t dns_hash(dns_dispatch_t *, isc_sockaddr_t *, isc_uint32_t);
 static void free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len);
 static void *allocate_buffer(dns_dispatch_t *disp, unsigned int len);
 static inline void free_event(dns_dispatch_t *disp, dns_dispatchevent_t *ev);
@@ -138,16 +139,38 @@ reseed_lfsr(isc_lfsr_t *lfsr, void *arg)
 /*
  * Return an unpredictable message ID.
  */
-static inline dns_messageid_t
-randomid(dns_dispatch_t *disp)
+static isc_uint32_t
+dns_randomid(dns_dispatch_t *disp)
 {
 	isc_uint32_t id;
 
 	id = isc_lfsr_generate32(&disp->qid_lfsr1, &disp->qid_lfsr2);
 
-	return ((dns_messageid_t)(id & 0x0000ffff));
+	return (id & 0x0000ffffU);
 }
 
+/*
+ * Return a hash of the destination and message id.
+ */
+static isc_uint32_t
+dns_hash(dns_dispatch_t *disp, isc_sockaddr_t *dest, isc_uint32_t id)
+{
+	unsigned int ret;
+
+	ret = isc_sockaddr_hash(dest, ISC_TRUE);
+	ret ^= (id & 0x0000ffff); /* important to mask off garbage bits */
+	ret %= disp->qid_nbuckets;
+
+	INSIST(ret < disp->qid_nbuckets);
+
+	return (ret);
+}
+
+static dns_dispatchmethods_t dns_wire_methods = {
+	dns_randomid,
+	dns_hash
+};
+
 static dns_dispentry_t *
 linear_first(dns_dispatch_t *disp)
 {
@@ -187,23 +210,6 @@ linear_next(dns_dispatch_t *disp, dns_dispentry_t *resp)
 	return (NULL);
 }
 
-/*
- * Return a hash of the destination and message id.
- */
-static unsigned int
-hash(dns_dispatch_t *disp, isc_sockaddr_t *dest, dns_messageid_t id)
-{
-	unsigned int ret;
-
-	ret = isc_sockaddr_hash(dest, ISC_TRUE);
-	ret ^= (id & 0x0000ffff); /* important to mask off garbage bits */
-	ret %= disp->qid_nbuckets;
-
-	INSIST(ret < disp->qid_nbuckets);
-
-	return (ret);
-}
-
 /*
  * Called when refcount reaches 0 (and safe to destroy)
  */
@@ -476,7 +482,7 @@ udp_recv(isc_task_t *task, isc_event_t *ev_in)
 		/* query */
 	} else {
  		/* response */
-		bucket = hash(disp, &ev->address, id);
+		bucket = disp->methods.hash(disp, &ev->address, id);
 		resp = bucket_search(disp, &ev->address, id, bucket);
 		XDEBUG(("Search for response in bucket %d: %s\n",
 			bucket, (resp == NULL ? "NOT FOUND" : "FOUND")));
@@ -662,7 +668,7 @@ tcp_recv(isc_task_t *task, isc_event_t *ev_in)
 		/* query */
 	} else {
  		/* response */
-		bucket = hash(disp, &tcpmsg->address, id);
+		bucket = disp->methods.hash(disp, &tcpmsg->address, id);
 		resp = bucket_search(disp, &tcpmsg->address, id, bucket);
 		XDEBUG(("Search for response in bucket %d: %s\n",
 			bucket, (resp == NULL ? "NOT FOUND" : "FOUND")));
@@ -785,6 +791,7 @@ dns_dispatch_create(isc_mem_t *mctx, isc_socket_t *sock, isc_task_t *task,
 		    unsigned int maxbuffersize,
 		    unsigned int maxbuffers, unsigned int maxrequests,
 		    unsigned int buckets, unsigned int increment,
+		    dns_dispatchmethods_t *methods,
 		    dns_dispatch_t **dispp)
 {
 	dns_dispatch_t *disp;
@@ -831,6 +838,11 @@ dns_dispatch_create(isc_mem_t *mctx, isc_socket_t *sock, isc_task_t *task,
 	ISC_LIST_INIT(disp->rq_handlers);
 	ISC_LIST_INIT(disp->rq_events);
 
+	if (methods == NULL)
+		disp->methods = dns_wire_methods;
+	else
+		disp->methods = *methods;
+
 	disp->qid_table = isc_mem_get(disp->mctx,
 				      buckets * sizeof(dns_displist_t));
 	if (disp->qid_table == NULL) {
@@ -1023,8 +1035,8 @@ dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest,
 	/*
 	 * Try somewhat hard to find an unique ID.
 	 */
-	id = randomid(disp);
-	bucket = hash(disp, dest, id);
+	id = disp->methods.randomid(disp);
+	bucket = disp->methods.hash(disp, dest, id);
 	ok = ISC_FALSE;
 	for (i = 0 ; i < 64 ; i++) {
 		if (bucket_search(disp, dest, id, bucket) == NULL) {
@@ -1033,7 +1045,7 @@ dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest,
 		}
 		id += disp->qid_increment;
 		id &= 0x0000ffff;
-		bucket = hash(disp, dest, id);
+		bucket = disp->methods.hash(disp, dest, id);
 	}
 
 	if (!ok) {
diff --git a/lib/dns/include/dns/dispatch.h b/lib/dns/include/dns/dispatch.h
index 35d80a97b6..ea975448b6 100644
--- a/lib/dns/include/dns/dispatch.h
+++ b/lib/dns/include/dns/dispatch.h
@@ -82,16 +82,32 @@ ISC_LANG_BEGINDECLS
 struct dns_dispatchevent {
 	ISC_EVENT_COMMON(dns_dispatchevent_t);	/* standard event common */
 	isc_result_t		result;		/* result code */
-	isc_int16_t		id;		/* message id */
+	isc_int32_t		id;		/* message id */
 	isc_sockaddr_t		addr;		/* address recv'd from */
 	isc_buffer_t	        buffer;		/* data buffer */
 };
 
+/*
+ * Functions to:
+ *
+ *	Return if a packet is a query or a response,
+ *	Hash IDs,
+ *	Generate a new random ID,
+ *	Compare entries (IDs) for equality,
+ */
+struct dns_dispatchmethods {
+	isc_uint32_t (*randomid)(dns_dispatch_t *);
+	isc_uint32_t (*hash)(dns_dispatch_t *, isc_sockaddr_t *,
+			     isc_uint32_t);
+};
+typedef struct dns_dispatchmethods dns_dispatchmethods_t;
+
 isc_result_t
 dns_dispatch_create(isc_mem_t *mctx, isc_socket_t *sock, isc_task_t *task,
 		    unsigned int maxbuffersize,
 		    unsigned int maxbuffers, unsigned int maxrequests,
 		    unsigned int buckets, unsigned int increment,
+		    dns_dispatchmethods_t *methods,
 		    dns_dispatch_t **dispp);
 /*
  * Create a new dns_dispatch and attach it to the provided isc_socket_t.
@@ -108,6 +124,10 @@ dns_dispatch_create(isc_mem_t *mctx, isc_socket_t *sock, isc_task_t *task,
  * "increment" is used in a collision avoidance function, and needs to be
  * a prime > buckets, and not 2.
  *
+ * "methods" be NULL for normal DNS wire format, or all elements in that
+ * structure be filled in with function pointers to control dispatch
+ * behavior.
+ *
  * Requires:
  *
  *	mctx is a valid memory context.
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 87e4524fee..99c77db96d 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -593,7 +593,7 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
 		if (result != ISC_R_SUCCESS)
 			goto cleanup_query;
 		result = dns_dispatch_create(res->mctx, socket, task,
-					     4096, 2, 1, 1, 3,
+					     4096, 2, 1, 1, 3, NULL,
 					     &query->dispatch);
 		/*
 		 * Regardless of whether dns_dispatch_create() succeeded or
@@ -3296,7 +3296,7 @@ dns_resolver_create(dns_view_t *view,
 		}
 		result = dns_dispatch_create(res->mctx, res->udpsocket4,
 					     res->buckets[0].task, 4096,
-					     1000, 32768, 16411, 16433,
+					     1000, 32768, 16411, 16433, NULL,
 					     &res->dispatch4);
 		if (result != ISC_R_SUCCESS)
 			goto cleanup_udpsocket4;
@@ -3318,7 +3318,7 @@ dns_resolver_create(dns_view_t *view,
 			goto cleanup_dispatch4;
 		result = dns_dispatch_create(res->mctx, res->udpsocket6,
 					     res->buckets[0].task, 4096, 
-					     1000, 32768, 16411, 16433,
+					     1000, 32768, 16411, 16433, NULL,
 					     &res->dispatch6);
 		if (result != ISC_R_SUCCESS)
 			goto cleanup_udpsocket6;