diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index 6d2bd9ad9f..4ceb182e7b 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -2262,6 +2262,14 @@ isc__nmsocket_readtimeout_cb(uv_timer_t *timer);
 void
 isc__nmsocket_writetimeout_cb(void *data, isc_result_t eresult);
 
+/*%<
+ *
+ * Maximum number of simultaneous handles in flight supported for a single
+ * connected TCPDNS socket. This value was chosen arbitrarily, and may be
+ * changed in the future.
+ */
+#define STREAM_CLIENTS_PER_CONN 23
+
 #define UV_RUNTIME_CHECK(func, ret)                                      \
 	if (ret != 0) {                                                  \
 		FATAL_ERROR("%s failed: %s\n", #func, uv_strerror(ret)); \
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 7b09639440..336cad4e23 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -2343,8 +2343,10 @@ processbuffer(isc_nmsocket_t *sock) {
  * timers. If we do have a full message, reset the timer.
  *
  * Stop reading if this is a client socket, or if the server socket
- * has been set to sequential mode. In this case we'll be called again
- * later by isc__nm_resume_processing().
+ * has been set to sequential mode, or the number of queries we are
+ * processing simultaneously has reached the clients-per-connection
+ * limit. In this case we'll be called again later by
+ * isc__nm_resume_processing().
  */
 isc_result_t
 isc__nm_process_sock_buffer(isc_nmsocket_t *sock) {
@@ -2384,7 +2386,8 @@ isc__nm_process_sock_buffer(isc_nmsocket_t *sock) {
 			isc__nmsocket_timer_stop(sock);
 
 			if (atomic_load(&sock->client) ||
-			    atomic_load(&sock->sequential))
+			    atomic_load(&sock->sequential) ||
+			    atomic_load(&sock->ah) >= STREAM_CLIENTS_PER_CONN)
 			{
 				isc__nm_stop_reading(sock);
 				goto done;