diff --git a/synapse.subdomain.conf.sample b/synapse.subdomain.conf.sample
index ca01b50..dadcb1e 100644
--- a/synapse.subdomain.conf.sample
+++ b/synapse.subdomain.conf.sample
@@ -5,8 +5,8 @@ server {
     listen [::]:443 ssl;
 
     # For the federation port
-    listen 8448 ssl;
-    listen [::]:8448 ssl;
+    listen 8448 ssl http2 default_server;
+    listen [::]:8448 ssl http2 default_server;
 
     server_name matrix.*;