diff --git a/app/models/account_authorization_config.rb b/app/models/account_authorization_config.rb
index 9f3aa61e965..9b506a15412 100644
--- a/app/models/account_authorization_config.rb
+++ b/app/models/account_authorization_config.rb
@@ -21,6 +21,7 @@ require 'net_ldap_extensions'
 
 class AccountAuthorizationConfig < ActiveRecord::Base
   include Workflow
+  validates :auth_filter, length: {maximum: maximum_text_length, allow_nil: true, allow_blank: true}
 
   strong_params
 
diff --git a/db/migrate/20150925063254_change_auth_filter_to_text.rb b/db/migrate/20150925063254_change_auth_filter_to_text.rb
new file mode 100644
index 00000000000..ea735d6b26f
--- /dev/null
+++ b/db/migrate/20150925063254_change_auth_filter_to_text.rb
@@ -0,0 +1,11 @@
+class ChangeAuthFilterToText < ActiveRecord::Migration
+  tag :postdeploy
+
+  def self.up
+    change_column :account_authorization_configs, :auth_filter, :text
+  end
+
+  def self.down
+    change_column :account_authorization_configs, :auth_filter, :string
+  end
+end