Server-Side Email Filters

Server-side email filtering is very useful if you access your email via IMAP from multiple devices. The most common use for a server-side filter is to auto-reply with a vacation message when you're going to be away from your email.
To use server-side email filters:

Now your default filter set is active, but has no filters defined. Add a filter by clicking the "+" at the bottom of the "Filters" column. To create a vacation message, use the following settings:

Filter name: Vacation
For incoming mail: all messages
...execute the following actions: Reply with message

Message body: (whatever you want)
Message subject: (whatever you want)
My additional email addresses:
How often send messages: 7 (if someone emails you every day, this number tells the server how many days to wait until sending your vacation message to that person again. I recommend at least 7, but you can set it lower if you like.)

Be sure the "Filter disabled" box is not checked, then click the "Save" button.

Now, finally, your vacation message is ready to use. You can enable/disable it using the filter configuration.