diff --git a/include/types/connection.h b/include/types/connection.h
index cf5dbb6..46d74fe 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -429,9 +429,17 @@
 	ALPN_MODE_ANY  = ALPN_MODE_TCP | ALPN_MODE_HTTP,
 };
 
+enum alpn_proxy_side {
+	ALPN_SIDE_NONE = 0,
+	ALPN_SIDE_FE   = 1, // same as PR_CAP_FE
+	ALPN_SIDE_BE   = 2, // same as PR_CAP_BE
+	ALPN_SIDE_BOTH = ALPN_SIDE_FE | ALPN_SIDE_BE,
+};
+
 struct alpn_mux_list {
 	const struct ist token;    /* token name and length. Empty is catch-all */
 	enum alpn_proxy_mode mode;
+	enum alpn_proxy_side side;
 	const struct mux_ops *mux;
 	struct list list;
 };
diff --git a/src/mux_h2.c b/src/mux_h2.c
index f46504c..192578b 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3603,7 +3603,7 @@
 
 /* ALPN selection : this mux registers ALPN tolen "h2" */
 static struct alpn_mux_list alpn_mux_h2 =
-	{ .token = IST("h2"), .mode = ALPN_MODE_HTTP, .mux = &h2_ops };
+	{ .token = IST("h2"), .mode = ALPN_MODE_HTTP, .side = ALPN_SIDE_FE, .mux = &h2_ops };
 
 /* config keyword parsers */
 static struct cfg_kw_list cfg_kws = {ILH, {
diff --git a/src/mux_pt.c b/src/mux_pt.c
index d6c1f83..131b070 100644
--- a/src/mux_pt.c
+++ b/src/mux_pt.c
@@ -217,7 +217,7 @@
 
 /* ALPN selection : default mux has empty name */
 static struct alpn_mux_list alpn_mux_pt =
-	{ .token = IST(""), .mode = ALPN_MODE_ANY, .mux = &mux_pt_ops };
+	{ .token = IST(""), .mode = ALPN_MODE_ANY, .side = ALPN_SIDE_BOTH, .mux = &mux_pt_ops };
 
 __attribute__((constructor))
 static void __mux_pt_init(void)