diff -urN src/globals.c.orig src/globals.c
--- src/globals.c.orig	Thu Jun 24 11:46:38 2004
+++ src/globals.c	Thu Jun 24 11:46:53 2004
@@ -318,7 +318,10 @@
 int     callout_cache_positive_expire = 24*60*60;
 int     callout_cache_negative_expire = 2*60*60;
 uschar *callout_random_local_part = US"$primary_hostname-$tod_epoch-testing";
+/*
 uschar *check_dns_names_pattern= US"(?i)^(?>(?(1)\\.|())[^\\W_](?>[a-z0-9-]*[^\\W_])?)+$";
+*/
+uschar *check_dns_names_pattern= US"(?i)^(?>(?(1)\\.|())[^\\W](?>[a-z0-9-]*[^\\W])?)+$";
 int     check_log_inodes       = 0;
 int     check_log_space        = 0;
 int     check_spool_inodes     = 0;