diff --git a/cf/m4/proto.m4 b/cf/m4/proto.m4
index ff7eb0b..58708e3 100644
--- a/cf/m4/proto.m4
+++ b/cf/m4/proto.m4
@@ -1924,6 +1924,8 @@ R<@> < $* @ [IPv6:::1] >
$: < ? $&{client_name} > < $1 @ [IPv6:::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 >')