diff --git a/lib/nghttp2_option.c b/lib/nghttp2_option.c
index 65200942..e8d6ed16 100644
--- a/lib/nghttp2_option.c
+++ b/lib/nghttp2_option.c
@@ -24,6 +24,8 @@
  */
 #include "nghttp2_option.h"
 
+#include "nghttp2_session.h"
+
 int nghttp2_option_new(nghttp2_option **option_ptr) {
   *option_ptr = calloc(1, sizeof(nghttp2_option));
 
@@ -79,12 +81,14 @@ void nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
 
 void nghttp2_option_set_builtin_recv_extension_type(nghttp2_option *option,
                                                     uint8_t type) {
-  if (type < 10) {
+  switch (type) {
+  case NGHTTP2_ALTSVC:
+    option->opt_set_mask |= NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES;
+    option->builtin_recv_ext_types |= NGHTTP2_TYPEMASK_ALTSVC;
+    return;
+  default:
     return;
   }
-
-  option->opt_set_mask |= NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES;
-  set_ext_type(option->builtin_recv_ext_types, type);
 }
 
 void nghttp2_option_set_no_auto_ping_ack(nghttp2_option *option, int val) {
diff --git a/lib/nghttp2_option.h b/lib/nghttp2_option.h
index b7d69610..87ef4e04 100644
--- a/lib/nghttp2_option.h
+++ b/lib/nghttp2_option.h
@@ -82,6 +82,10 @@ struct nghttp2_option {
    * NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS
    */
   uint32_t max_reserved_remote_streams;
+  /**
+   * NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES
+   */
+  uint32_t builtin_recv_ext_types;
   /**
    * NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE
    */
@@ -102,10 +106,6 @@ struct nghttp2_option {
    * NGHTTP2_OPT_USER_RECV_EXT_TYPES
    */
   uint8_t user_recv_ext_types[32];
-  /**
-   * NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES
-   */
-  uint8_t builtin_recv_ext_types[32];
 };
 
 #endif /* NGHTTP2_OPTION_H */
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 8af22bd7..d204596a 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -323,10 +323,12 @@ static void session_inbound_frame_reset(nghttp2_session *session) {
     if (check_ext_type_set(session->user_recv_ext_types,
                            iframe->frame.hd.type)) {
       nghttp2_frame_extension_free(&iframe->frame.ext);
-    } else if (check_ext_type_set(session->builtin_recv_ext_types,
-                                  iframe->frame.hd.type)) {
+    } else {
       switch (iframe->frame.hd.type) {
       case NGHTTP2_ALTSVC:
+        if ((session->builtin_recv_ext_types & NGHTTP2_TYPEMASK_ALTSVC) == 0) {
+          break;
+        }
         nghttp2_frame_altsvc_free(&iframe->frame.ext, mem);
         break;
       }
@@ -492,9 +494,7 @@ static int session_new(nghttp2_session **session_ptr,
     }
 
     if (option->opt_set_mask & NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES) {
-      memcpy((*session_ptr)->builtin_recv_ext_types,
-             option->builtin_recv_ext_types,
-             sizeof((*session_ptr)->builtin_recv_ext_types));
+      (*session_ptr)->builtin_recv_ext_types = option->builtin_recv_ext_types;
     }
 
     if ((option->opt_set_mask & NGHTTP2_OPT_NO_AUTO_PING_ACK) &&
@@ -5556,10 +5556,16 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           iframe->state = NGHTTP2_IB_READ_EXTENSION_PAYLOAD;
 
           break;
-        } else if (check_ext_type_set(session->builtin_recv_ext_types,
-                                      iframe->frame.hd.type)) {
+        } else {
           switch (iframe->frame.hd.type) {
           case NGHTTP2_ALTSVC:
+            if ((session->builtin_recv_ext_types & NGHTTP2_TYPEMASK_ALTSVC) ==
+                0) {
+              busy = 1;
+              iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+              break;
+            }
+
             DEBUGF(fprintf(stderr, "recv: ALTSVC\n"));
 
             iframe->frame.hd.flags = NGHTTP2_FLAG_NONE;
@@ -5590,12 +5596,6 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
             break;
           }
-        } else {
-          busy = 1;
-
-          iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
-
-          break;
         }
       }
 
diff --git a/lib/nghttp2_session.h b/lib/nghttp2_session.h
index 1e391dcb..a5cb1aec 100644
--- a/lib/nghttp2_session.h
+++ b/lib/nghttp2_session.h
@@ -54,6 +54,15 @@ typedef enum {
   NGHTTP2_OPTMASK_NO_AUTO_PING_ACK = 1 << 3
 } nghttp2_optmask;
 
+/*
+ * bitmask for built-in type to enable the default handling for that
+ * type of the frame.
+ */
+typedef enum {
+  NGHTTP2_TYPEMASK_NONE = 0,
+  NGHTTP2_TYPEMASK_ALTSVC = 1 << 0
+} nghttp2_typemask;
+
 typedef enum {
   NGHTTP2_OB_POP_ITEM,
   NGHTTP2_OB_SEND_DATA,
@@ -295,6 +304,9 @@ struct nghttp2_session {
   /* Unacked local SETTINGS_MAX_CONCURRENT_STREAMS value. We use this
      to refuse the incoming stream if it exceeds this value. */
   uint32_t pending_local_max_concurrent_stream;
+  /* The bitwose OR of zero or more of nghttp2_typemask to indicate
+     that the default handling of extension frame is enabled. */
+  uint32_t builtin_recv_ext_types;
   /* Unacked local ENABLE_PUSH value.  We use this to refuse
      PUSH_PROMISE before SETTINGS ACK is received. */
   uint8_t pending_enable_push;
@@ -314,7 +326,6 @@ struct nghttp2_session {
      bit is set, it indicates that incoming frame with that type is
      passed to user defined callbacks, otherwise they are ignored. */
   uint8_t user_recv_ext_types[32];
-  uint8_t builtin_recv_ext_types[32];
 };
 
 /* Struct used when updating initial window size of each active