diff --git a/doc/tinyproxy.conf b/doc/tinyproxy.conf
index cd48c12..e17efd2 100644
--- a/doc/tinyproxy.conf
+++ b/doc/tinyproxy.conf
@@ -61,10 +61,17 @@ PidFile "/var/run/tinyproxy.pid"
 
 #
 # Turns tinyproxy into a TCP tunnel which connects the local computer on
-# 'Port' to the remote computer's port. The form is remote_machine port
+# 'Port' to the remote computer's port. No processing is done when using
+# tinyproxy as a tunnel. If you want to connect to an upstream proxy use
+# the "Upstream" directive below.
 #
 #Tunnel some.remote.computer:port
 
+#
+# Turns on upstream proxy support.
+#
+#Upstream some.remote.proxy:port
+
 #
 # This is the absolute highest number of threads which will be created. In
 # other words, only MaxClients number of clients can be connected at the