diff --git a/changelog.d/11128.doc b/changelog.d/11128.doc
new file mode 100644
index 0000000000..c024679218
--- /dev/null
+++ b/changelog.d/11128.doc
@@ -0,0 +1 @@
+Improve example HAProxy config in the docs to properly handle host headers with port information. This is required for federation over port 443 to work correctly.
diff --git a/docs/reverse_proxy.md b/docs/reverse_proxy.md
index 9f18fa1818..f3b3aea732 100644
--- a/docs/reverse_proxy.md
+++ b/docs/reverse_proxy.md
@@ -188,7 +188,7 @@ frontend https
   http-request set-header X-Forwarded-For %[src]
 
   # Matrix client traffic
-  acl matrix-host hdr(host) -i matrix.example.com
+  acl matrix-host hdr(host) -i matrix.example.com matrix.example.com:443
   acl matrix-path path_beg /_matrix
   acl matrix-path path_beg /_synapse/client