diff -up sudo-1.8.6p3/plugins/sudoers/match.c.nonehostname sudo-1.8.6p3/plugins/sudoers/match.c
--- sudo-1.8.6p3/plugins/sudoers/match.c.nonehostname	2014-05-19 12:50:08.412313041 +0200
+++ sudo-1.8.6p3/plugins/sudoers/match.c	2014-05-19 12:50:17.787348134 +0200
@@ -727,7 +727,8 @@ netgr_matches(char *netgr, char *lhost,
     /* get the domain name (if any) */
     if (!initialized) {
 	domain = (char *) emalloc(MAXHOSTNAMELEN + 1);
-	if (getdomainname(domain, MAXHOSTNAMELEN + 1) == -1 || *domain == '\0') {
+	if (getdomainname(domain, MAXHOSTNAMELEN + 1) == -1 || *domain == '\0'
+	    || strncmp (domain, "(none)", 7) == 0) {
 	    efree(domain);
 	    domain = NULL;
 	}