diff -rup mutt-1.5.23/init.c mutt-1.5.23-new/init.c
--- mutt-1.5.23/init.c	2014-03-12 17:03:45.000000000 +0100
+++ mutt-1.5.23-new/init.c	2015-06-01 12:28:34.178727003 +0200
@@ -2890,7 +2890,8 @@ void mutt_init (int skip_sys_rc, LIST *c
 {
   struct passwd *pw;
   struct utsname utsname;
-  char *p, buffer[STRING];
+  char *p;
+  char buffer[STRING] = "";
   int i, default_rc = 0, need_pause = 0;
   BUFFER err;
 
@@ -2968,11 +2969,11 @@ void mutt_init (int skip_sys_rc, LIST *c
 
 #ifndef DOMAIN
 #define DOMAIN buffer
-  if (!p && getdnsdomainname (buffer, sizeof (buffer)) == -1)
+  if (p == NULL  && getdnsdomainname (buffer, sizeof (buffer)) == -1 && strlen(Hostname) == 0)
     Fqdn = safe_strdup ("@");
   else
 #endif /* DOMAIN */
-    if (*DOMAIN != '@')
+    if (*DOMAIN != '@' && strlen(DOMAIN) != 0)
   {
     Fqdn = safe_malloc (mutt_strlen (DOMAIN) + mutt_strlen (Hostname) + 2);
     sprintf (Fqdn, "%s.%s", NONULL(Hostname), DOMAIN);	/* __SPRINTF_CHECKED__ */