How to Create an Email Mailbox With an Autoresponder and Forwarding in ISPConfig

This guide shows you how to create an email mailbox in ISPConfig that replies to every sender with an automatic message and forwards a copy of each incoming message to another address. It is the pattern to use when you are retiring an address (for example, a staff member has left) but you still want incoming mail routed to someone else and senders told the address is no longer monitored.

In ISPConfig the relevant fields use their own names: Send copy to is a forward (a carbon copy of each message), and Autoresponder is the automatic reply (sometimes called a vacation or out-of-office message). A third field, Disable (local) delivering, stops mail being saved in the mailbox itself, and it is the one people reach for to stop a retired mailbox filling up. Leave it alone here: ticking it also switches the autoresponder off. The reason is set out under Why local delivery must stay on below. For a plain mailbox without these extras, start with the basic guide, How to Create an Email Mailbox in ISPConfig.

Last reviewed: 27 July 2026, against ISPConfig 3.3.1p1 (the release running on Noiz servers). This guide is written for Noiz hosting and is kept current against ISPConfig. It complements, and does not replace, the official ISPConfig documentation linked below.

Official Documentation Reference

• ISPConfig documentation portal
• ISPConfig manual (field-by-field reference for the Email module)
• ISPConfig frequently asked questions

Prerequisites

• Login details for your ISPConfig control panel (client or admin level).
• The email domain already added to your account, so that it appears in the domain dropdown.
• The destination address you want to forward to. This can be on the same domain or an external address, such as a Gmail account.

Step-by-Step Instructions

1. Log in to your ISPConfig control panel

   • Open your web browser and go to your ISPConfig panel address (for example, https://yourserver:8080).
   • Enter your username and password, then click Login.

2. Open the Email module

   • From the top menu, click Email.
   • In the left-hand menu, select Email Mailbox.
   • Click Add new Mailbox.

3. Enter the mailbox name and password

   • In the Name field, type a display name (optional).
   • In the Email field, type the local part of the address (for example, info) and choose the domain from the dropdown, giving you [email protected].
   • Set a strong password in the Password and Repeat Password fields, or click Generate Password. A password is always required, even on an address nobody will log in to.
   • Set Quota (0 for unlimited) in MB. This mailbox does keep a copy of everything it forwards, so give it a realistic size rather than treating it as empty.

4. Set the forwarding (Send copy to) address

   • In the Send copy to field, enter the address that should receive the mail (for example, [email protected]). More than one address is allowed here, separated by commas.
   • Leave Copy during delivery as you find it. It only decides whether the copy is taken before or during delivery to the mailbox, and either setting forwards the mail.
   • Leave Send outgoing BCC to blank unless your organisation has a specific archiving or compliance requirement. It takes one address only, and it copies mail sent from this account, not mail arriving at it.

5. Configure the autoresponder

   • Click the Autoresponder tab.
   • Tick Enable the autoresponder.
   • In Email Subject, enter a subject line (for example, This mailbox is no longer monitored).
   • In Text, enter the reply body (for example, Thank you for your email. This address is no longer monitored. Please write to [email protected] instead.).
   • Set Start on and End by only if the reply should run for a limited period. Leave both blank for a permanent reply. Start on will not accept a date in the past, and End by must be later than Start on. Once the End by date has passed, no further replies go out.

6. Check the delivery options

   • Return to the Mailbox tab and scroll to the options near the bottom.
   • Leave Disable (local) delivering unticked. This is the important one. Ticking it hands the message straight to the forward address and never delivers it to the mailbox, and the autoresponder only runs as part of that local delivery, so ticking it silently switches the automatic reply off.
   • Leave Enable receiving ticked, or there is nothing to forward or answer in the first place.
   • Leave Disable sending unticked. It looks harmless on an address nobody sends from, but with the default Copy during delivery setting it also breaks the forward, because ISPConfig only passes the Send copy to address to the mail server while sending is allowed on the account.
   • Leave Enable greylisting, Disable IMAP and Disable POP3 unticked unless you have a specific reason to change them. Greylisting in particular is best left off on a forwarding address, so that forwards are not delayed.

7. Save and test

   • Click Save.
   • Wait a minute or two. ISPConfig applies mailbox changes to the mail server through a background job queue, so they are not always instant.
   • From an outside account, send a test message to the address.
   • Confirm that the sender receives the automatic reply, and that the message arrives at the Send copy to address. A copy is also kept in the mailbox itself, which you can check by webmail if you want a third confirmation.

How This Combination Works

On its own, a mailbox stores mail and lets someone read it. The two settings above add to that behaviour:

• Send copy to forwards a copy of every incoming message to the address you specify. The original is still delivered to the mailbox, so the mail is in two places and nothing is lost if the forward target has a bad day.
• The Autoresponder replies to the sender, so people writing to the old address are told where to go next. That reply is produced while the message is being delivered into the mailbox, not by the forward.

The result is a graceful retirement of an address. No one loses the mail, and senders are told where to write instead.

Why local delivery must stay on

Disable (local) delivering looks like the obvious third ingredient, since it stops the retired mailbox filling up. It does more than that. Ticking it moves the whole job up to the mail server: the message is redirected to the Send copy to address before the mailbox is involved at all, so mailbox rules are never reached. ISPConfig says this in the field's own tooltip, which notes that it disables delivery to the inbox and the processing of mail filters and rules. The autoresponder is one of those rules, so it never runs.

That leaves two honest choices rather than one:

• Reply and forward. Leave Disable (local) delivering unticked, as in the steps above. Mail is answered, forwarded, and also kept. This is what most address retirements want.
• Forward only, nothing kept. Tick Disable (local) delivering and accept that there will be no automatic reply. If that is all you need, Email then Email Forward does the same job without creating a mailbox, a password or a quota at all.

Points to Watch

• The mailbox does fill up. Because local delivery stays on, every message it forwards is also stored. Set a Quota you are happy with and empty the mailbox occasionally, or the address will eventually start refusing mail.
• Replies are rate limited. Any one sender gets at most one automatic reply per day, however many messages they send, so nobody is flooded and reply loops do not build up. Anything already flagged as spam is never answered, and automated and mailing list messages are left alone too.
• Aliases are covered. If other addresses or alias domains point at this mailbox, the autoresponder treats those as the same person and replies for them as well.
• The reply comes from the retired address. Recipients see the automatic reply as coming from the address you are retiring, which is expected. Always point them to a monitored address in the reply text.
• Changes are queued. If a test does not behave as expected straight away, wait a moment and try again before changing settings.

Troubleshooting

• The autoresponse never arrives. Check Disable (local) delivering on the Mailbox tab first, because ticking it switches the autoresponder off and is by far the most common cause. Then check that Enable the autoresponder is ticked and that End by has not already passed. Remember that a given sender is only answered once a day, and that spam, automated senders and mailing lists are deliberately not answered.
• Forwarded mail is not received. Confirm the Send copy to address is entered correctly and is active, and that Disable sending is unticked, since that setting stops the forward as well. Ask the recipient to check their spam or junk folder, because forwarded mail can score higher there.
• The sender gets a bounce. If the forward target is rejecting the mail or cannot be reached, the sender is told about that copy even though the mailbox copy was delivered normally. Correct or replace the forward address. A bounce can also mean the mailbox has hit its Quota.
• Nothing changed after saving. Give ISPConfig a minute to apply the queued job, then test again.

Need a Hand?

If you are on a managed Noiz hosting plan and would like this configured for you, or you are unsure which forwarding pattern suits your situation, open a support ticket from your Noiz client area and the team will set it up with you.

Reference Screenshot

The ISPConfig 3.3 Mailbox configuration screen: