diff --git a/src/calibre/srv/opts.py b/src/calibre/srv/opts.py
index 6445144dea..9dfb15ff57 100644
--- a/src/calibre/srv/opts.py
+++ b/src/calibre/srv/opts.py
@@ -112,7 +112,7 @@ raw_options = (
 
     _('The interface on which to listen for connections'),
     'listen_on', '0.0.0.0',
-    _('The default is to listen on all available interfaces. You can change this to, for'
+    _('The default is to listen on all available IPv4 interfaces. You can change this to, for'
     ' example, "127.0.0.1" to only listen for connections from the local machine, or'
     ' to "::" to listen to all incoming IPv6 and IPv4 connections.'),