diff --git a/cf/m4/proto.m4 b/cf/m4/proto.m4
index 79667c1..e7be2a4 100644
--- a/cf/m4/proto.m4
+++ b/cf/m4/proto.m4
@@ -1863,6 +1863,8 @@ R<@> < $* @ [127.0.0.1] >
 			$: < ? $&{client_name} > < $1 @ [127.0.0.1] >
 R<@> < $* @ localhost.$m >
 			$: < ? $&{client_name} > < $1 @ localhost.$m >
+R<@> < $* @ localhost.localdomain >
+			$: < ? $&{client_name} > < $1 @ localhost.localdomain >
 ifdef(`_NO_UUCP_', `dnl',
 `R<@> < $* @ localhost.UUCP >
 			$: < ? $&{client_name} > < $1 @ localhost.UUCP >')