If you use webmail to access your email and you'd like to set up an auto-responder please see the instructions below.
Auto-responders are a reply that's sent to anyone who emails you, with a message explaining that you're out of the office / on holiday etc.
Instructions for setting up an auto-responder in Webmail, whether you use Horde, Squirrel Mail or Round Cube:
1. Log into Webmail (http://www.yourwebsite.com/webmail or http://webmail.yourwebsite.com depending on your website). On the first screen you see click on the Auto-Responders icon, highlighted in the image below with a red box around it:

2. The next screen will show you any auto-responders you already have set up (if any). To add a new one, click the "Add Autoresponder" button:

3. In the form that appears, fill in "from", "subject" and "message" and click "Create/Modify".
Eg. From: Lisa Bailey | 18a Productions Ltd.
Subject: Out of the office
Message: I am currently out of the office until Tuesday and will reply to your email on my return.

4. Then you're done! Remember to come back and turn off your auto-responder once it's out of date. It'll show in the list we talked about in Step 2 (that was probably empty this time!).