diff --git a/Documentation/config/http.txt b/Documentation/config/http.txt
index 2d4e0c9b86..a9c7480f6a 100644
--- a/Documentation/config/http.txt
+++ b/Documentation/config/http.txt
@@ -7,6 +7,11 @@ http.proxy::
 	linkgit:gitcredentials[7] for more information. The syntax thus is
 	'[protocol://][user[:password]@]proxyhost[:port]'. This can be overridden
 	on a per-remote basis; see remote.<name>.proxy
++
+Any proxy, however configured, must be completely transparent and must not
+modify, transform, or buffer the request or response in any way.  Proxies which
+are not completely transparent are known to cause various forms of breakage
+with Git.
 
 http.proxyAuthMethod::
 	Set the method with which to authenticate against the HTTP proxy. This