diff --git a/include/types/connection.h b/include/types/connection.h
index c7d968c..1a1409b 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -294,6 +294,7 @@
 enum {
 	MX_FL_NONE        = 0x00000000,
 	MX_FL_CLEAN_ABRT  = 0x00000001, /* abort is clearly reported as an error */
+	MX_FL_HTX         = 0x00000002, /* set if it is an HTX multiplexer */
 };
 
 /* xprt_ops describes transport-layer operations for a connection. They
diff --git a/src/mux_h1.c b/src/mux_h1.c
index d6ea268..4dcbcaf 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -2343,7 +2343,7 @@
 	.shutw       = h1_shutw,
 	.show_fd     = h1_show_fd,
 	.reset       = h1_reset,
-	.flags       = MX_FL_NONE,
+	.flags       = MX_FL_HTX,
 	.name        = "h1",
 };
 
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 1e81128..3e50150 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -5682,7 +5682,7 @@
 	.shutr = h2_shutr,
 	.shutw = h2_shutw,
 	.show_fd = h2_show_fd,
-	.flags = MX_FL_CLEAN_ABRT,
+	.flags = MX_FL_CLEAN_ABRT|MX_FL_HTX,
 	.name = "H2",
 };