diff --git a/docs/reference/setup/configuration.asciidoc b/docs/reference/setup/configuration.asciidoc
index 375caf5b75a..dc5c242af4e 100644
--- a/docs/reference/setup/configuration.asciidoc
+++ b/docs/reference/setup/configuration.asciidoc
@@ -133,6 +133,10 @@ appender.rolling.policies.time.modulate = true <6>
 <6> Align rolls on the day boundary (as opposed to rolling every twenty-four
     hours)
 
+NOTE: Log4j's configuration parsing gets confused by any extraneous whitespace;
+if you copy and paste the above settings, or enter any Log4j configuration in
+general, be sure to trim any leading and trailing whitespace.
+
 If you append `.gz` or `.zip` to `appender.rolling.filePattern`, then the logs
 will be compressed as they are rolled.