How do I send an automatic reply to people who send me e-mail?

The autoresponder can send an automatic reply to each message that arrives. You can use this feature to tell people you're on vacation until a certain date, for example.

You can enable the autoresponder for any address except the catch-all address. To do so:

Autoresponder restrictions

To minimize the possibility of bothering people or creating an infinite loop of dueling autoresponder messages, the autoresponder won't send a reply:

  • If it has already sent the reply to the same "From:" or "Return-Path:" e-mail address in the last week;
  • If it has already sent the reply more than 30 times (to any addresses) in the last hour;
  • If the original message appears to come from a mailing list or appears to be automatically generated by a script, program or mail server (including "bounce" messages);
  • If the original message appears to be spam, based on its SpamAssassin score; or
  • If your address does not appear in the "To" or "CC" headers of the original message (this helps ensure that it won't mistakenly reply to automatically forwarded messages or mailing lists, but also means it won't reply to BCC or forwarded messages).

This means that you can't absolutely rely on people receiving an automatic reply when they send you messages (you can't anyway, because some people block incoming auto replies). Be sure you don't depend on it for something very important.

The first of these restrictions also means you won’t be able to test the autoresponder yourself more than once from the same address; it’s normal that only your first test will generate a reply.

(By the way, most of these restrictions are required by Internet RFC 3484; they're not arbitrary rules we made up.)

Autoresponders and FormMail

Occasionally we're asked if it's possible to use FormMail (or another e-mail sending script) and the autoresponder together. The idea would be to make the FormMail recipient be an autoresponder address so that the person filling out the form will receive an instant, automatically generated e-mail reply.

Unfortunately this won't work. FormMail uses the same internal sender address for each message, so the autoresponder wouldn't send more than one response a week no matter many people filled out the form. Even if you solved that problem, the autoresponder intentionally tries very hard to avoid sending responses to computer-generated messages, such as those created by scripts (including FormMail). This step is a security measure that's necessary to avoid infinite mail loops, as well as to avoid sending mail to fake addresses entered by spammers using automated scripts.

So using the e-mail autoresponder to try and send a message to a visitor who fills out a website form isn't really the right approach; you'd be trying to make the autoresponder do something it's specifically designed to avoid doing.

If you really need this functionality, the best approach is probably to use a different form script of your own choosing that directly sends the extra message to the user as part of the script, with no autoresponder involved. Many form scripts can do this.

However, we should mention that we don't really recommend this, either. Any script you place on a Web page is likely to get many submissions from spammers who use automated software to "fill out the form" with fake e-mail addresses in an effort to send you messages hawking Viagra and so forth. Unless your script has strong spam filtering protection, your "autoresponder" will end up sending messages to strangers at the fake addresses, which they'll probably report as "spam".

This has caused big problems for our customers in the past. For example, if a spammer "fills out" your form with fake gmail.com addresses, and your script sends messages to Gmail users who mark them as "spam", Gmail will probably block all future messages from you, damaging your business. We recommend thinking very carefully about whether you really need to send autoresponder messages to (often fake) addresses that are entered on your Web site; in most cases, it causes far more problems than it solves.

(Note that our e-mail script policies also require that you obtain our permission before using these kinds of scripts so we can verify they can't be "hijacked" by spammers to send bulk messages to strangers.)