Auto-responders and the like can be managed via the webmail interface.

Once you have logged in to webmail with your email username and password, go to 'Settings' in the top right and then click on 'Filters'. 

To create a new filter or rule, Click on the '+' button and give the new filter a name.

Vacation Auto-Responder.

To create an auto-responder while away on vacation, select 'All messages' and then 'Out of Office Message'. You can then enter a subject line and message which will be sent to the sender.