diff --git a/doc/src/sgml/client-auth.sgml b/doc/src/sgml/client-auth.sgml
index b2a459fb0d..433759928b 100644
--- a/doc/src/sgml/client-auth.sgml
+++ b/doc/src/sgml/client-auth.sgml
@@ -417,7 +417,9 @@ hostnogssenc database user
Specifies the authentication method to use when a connection matches
this record. The possible choices are summarized here; details
- are in .
+ are in . All the options
+ are lower case and treated case sensitively, so even acronyms like
+ ldap must be specified as lower case.