--- ubiquity/plugins/ubi-usersetup.py	2012-02-11 18:28:05.000000000 -0800
+++ ubiquity/plugins/ubi-usersetup.py.new	2012-02-17 17:28:54.498523145 -0800
@@ -228,6 +228,15 @@
             execute_root('apt-install', 'oem-config-gtk',
                                         'oem-config-slideshow-ubuntu')
 
+        # bug 760884
+        # On networks where DNS fakes a response for unknown hosts,
+        # don't display a warning for hostnames that already exist.
+        self.resolver_ok = False
+        hostname = "xyzzy_does_not_exist"
+        for host in (hostname, '%s.local' % hostname):
+            self.resolver.lookup_by_name_async(
+                host, None, self.bogus_lookup_result, None)
+
         self.plugin_widgets = self.page
 
     def plugin_translate(self, lang):
@@ -432,12 +441,19 @@
             self.hostname_ok.hide()
 
     def hostname_timeout(self, widget):
-        if self.hostname_ok.get_property('visible'):
+        if self.hostname_ok.get_property('visible') and self.resolver_ok:
             hostname = widget.get_text()
             for host in (hostname, '%s.local' % hostname):
                 self.resolver.lookup_by_name_async(
                     host, None, self.lookup_result, None)
 
+    def bogus_lookup_result(self, resolver, result, unused):
+        from gi.repository import GObject
+        try:
+            resolver.lookup_by_name_finish(result)
+        except GObject.GError:
+            self.resolver_ok = True
+
     def on_authentication_toggled(self, w):
         if w == self.login_auto and w.get_active():
             self.login_encrypt.set_active(False)