diff --git a/include/libwebsockets/lws-context-vhost.h b/include/libwebsockets/lws-context-vhost.h
index f98fb8da2..c0673a01e 100644
--- a/include/libwebsockets/lws-context-vhost.h
+++ b/include/libwebsockets/lws-context-vhost.h
@@ -334,7 +334,10 @@ struct lws_context_creation_info {
 	 *
 	 * You can also set port to 0, in which case the kernel will pick
 	 * a random port that is not already in use.  You can find out what
-	 * port the vhost is listening on using lws_get_vhost_listen_port() */
+	 * port the vhost is listening on using lws_get_vhost_listen_port()
+	 *
+	 * If options specifies LWS_SERVER_OPTION_UNIX_SOCK, you should set
+	 * port to 0 */
 
 	unsigned int http_proxy_port;
 	/**< VHOST: If http_proxy_address was non-NULL, uses this port */