diff -r 0f84e0e6400e app/controllers/users_controller.rb
--- a/app/controllers/users_controller.rb	Sun Sep 20 06:20:40 2015 +0000
+++ b/app/controllers/users_controller.rb	Fri Oct 23 12:28:55 2015 +0200
@@ -46,6 +46,7 @@
     scope = User.logged.status(@status).preload(:email_address)
     scope = scope.like(params[:name]) if params[:name].present?
     scope = scope.in_group(params[:group_id]) if params[:group_id].present?
+    scope = scope.auth_source(params[:auth_source]) if (params[:auth_source].present? && !params[:auth_source].blank?)
 
     @user_count = scope.count
     @user_pages = Paginator.new @user_count, @limit, params['page']
diff -r 0f84e0e6400e app/helpers/users_helper.rb
--- a/app/helpers/users_helper.rb	Sun Sep 20 06:20:40 2015 +0000
+++ b/app/helpers/users_helper.rb	Fri Oct 23 12:28:44 2015 +0200
@@ -26,6 +26,15 @@
                         ["#{l(:status_locked)} (#{user_count_by_status[3].to_i})", '3']], selected.to_s)
   end
 
+  def users_auth_sources_options_for_select(selected)
+    options = [[l(:label_all), ''],
+               [l(:label_internal), 'NULL']]
+    AuthSource.all.each do |as|
+      options << [as.name, as.id]
+    end
+    options_for_select(options, selected.to_s)
+  end
+
   def user_mail_notification_options(user)
     user.valid_notification_options.collect {|o| [l(o.last), o.first]}
   end
diff -r 0f84e0e6400e app/models/user.rb
--- a/app/models/user.rb	Sun Sep 20 06:20:40 2015 +0000
+++ b/app/models/user.rb	Fri Oct 23 12:29:06 2015 +0200
@@ -135,6 +135,13 @@
       none
     end
   }
+  scope :auth_source, lambda {|auth_source_id|
+    if (auth_source_id == 'NULL') 
+      where("#{User.table_name}.auth_source_id IS NULL", auth_source_id)
+    else
+      where("#{User.table_name}.auth_source_id = ?", auth_source_id)
+    end
+  }
 
   def set_mail_notification
     self.mail_notification = Setting.default_notification_option if self.mail_notification.blank?
diff -r 0f84e0e6400e app/views/users/index.html.erb
--- a/app/views/users/index.html.erb	Sun Sep 20 06:20:40 2015 +0000
+++ b/app/views/users/index.html.erb	Fri Oct 23 12:29:20 2015 +0200
@@ -16,6 +16,10 @@
 
 <label for='name'><%= l(:label_user) %>:</label>
 <%= text_field_tag 'name', params[:name], :size => 30 %>
+<label for='auth_source'><%= l(:label_auth_source) %>:</label>
+<%= select_tag 'auth_source', users_auth_sources_options_for_select(params[:auth_source]), :onchange => "this.form.submit(); return false;"  %>
+
+
 <%= submit_tag l(:button_apply), :class => "small", :name => nil %>
 <%= link_to l(:button_clear), users_path, :class => 'icon icon-reload' %>
 </fieldset>