History of email auto responders

September 28, 2023

Email auto responders are a powerful tool that can be used to automate a variety of tasks, such as welcoming new subscribers, nurturing leads, and sending out promotional offers. But how did email auto responders come about?

Procmail and Sieve

The earliest email auto responders were created using procmail and Sieve, which are both powerful mail filtering tools. Procmail is a command-line tool that can be used to create complex filtering rules, while Sieve is a scripting language that is designed specifically for filtering email.

To create an email auto responder using procmail or Sieve, you would need to write a script that tells the mail server how to respond to incoming email messages. For example, you could write a script that automatically sends a welcome email to anyone who subscribes to your mailing list, or a script that automatically sends a follow-up email to anyone who abandons their shopping cart on your website. See the following script:

require "vacation";

vacation.enable = true;
vacation.subject = "I am away from the office";
vacation.body = "I am currently away from the office and will not be able to respond to your email until [date of return]. I apologize for any inconvenience this may cause.";
vacation.min_interval = 1 day;

To use this Sieve script, you would need to save it as a file with a .sieve extension in your Dovecot mail server’s Sieve scripts directory. For example, you could save it as vacation.sieve.

Once you have saved the Sieve script, you would need to enable it for your email account. To do this, you would need to add the following line to your Dovecot mail server’s configuration file:

sieve = required,vacation

Once you have enabled the Sieve script, you can test it by sending yourself an email. If the Sieve script is working correctly, you should receive an automatic reply. See the following script:

# Vacation responder

:0c
* ^Subject: .*
* ^To: .*@[domain].com$

# Check if the recipient is in the vacation responder whitelist
if $MATCH
then
  exit 0
fi

# Set the vacation responder subject and body
set subject = "I am away from the office"
set body = "I am currently away from the office and will not be able to respond to your email until [date of return]. I apologize for any inconvenience this may cause."

# Send the vacation responder email
pipe "echo \"$body\" | mail -s \"$subject\" $TO"

To use this Procmail recipe, you would need to save it as a file with a .procmailrc extension in your home directory. For example, you could save it as .procmailrc.

Once you have saved the Procmail recipe, you would need to enable it for your email account. To do this, you would need to add the following line to your .procmailrc file:

INCLUDERC=/etc/procmailrc

Once you have enabled the Procmail recipe, you can test it by sending yourself an email. If the Procmail recipe is working correctly, you should receive an automatic reply.

Note that this, somewhat complex, configuration was usually abstracted away by the desktop or web email clients.

Outlook and GMail

Email auto responders were eventually incorporated into popular email clients such as Outlook and Gmail. This made it much easier for people to create and manage email auto responders, without having to learn how to use procmail or Sieve.

In Outlook, you can create an email auto responder by going to File > Info > Automatic Replies. In Gmail, you can create an email auto responder by going to Settings > See all settings > General > Vacation responder.