Here you can setup a vacation responder for a user. You can edit the following options:
Enable/Disable the vacation message.
Toggle whether the response will be sent to any sender or only those senders in the user's contacts.
Toggle whether the response will be sent to senders in any domain or only senders in the user's domain.
Toggle whether the response will be in plain text or rich text formatting.
Specify a first and last day for the responder to be active.
Create the subject and vacation message.
Due to limitations with Google's API, you must always supply a "Last Day". Also due to API limitations, when you set the days in gPanel and save, it will show up a day before in the Gmail UI. i.e. If you set the start date as September 10, 2015, it will show up as September 9, 2015 in Gmail.
Once you have made changes, click Save.