Inject a Test Message into Dovecot with doveadm save

Need to know whether a mailbox really accepts mail, without firing up an SMTP session? doveadm save drops one known message straight into a Dovecot mailbox. You will place it, confirm where it landed, and keep the whole test scoped to one user. The examples match the installed Dovecot 2.3.21 command from the dovecot-core package. Allow about ten minutes if the mailbox and test account already exist.

• You need: shell access to the Dovecot host, a valid mailbox user, and permission to run doveadm for that installation.
• What it touches: mail storage. Do not test against a real user's inbox unless that delivery is intentional.
• Best target: a disposable account or a clearly named test mailbox.

1. Check the installed command

Confirm the binary and version before copying an example. These are ordinary read-only commands and normally need no sudo:

$ command -v doveadm
/usr/bin/doveadm
$ doveadm --version
2.3.21 (47349e2482)
$ dpkg-query -W -f='${Package} ${Version}\n' dovecot-core
dovecot-core 1:2.3.21+dfsg1-2ubuntu6.5

2. Prepare a harmless message

A saved message still counts as mail. Create a complete, small RFC-style message with a distinctive subject. The command below only creates a file; it does not contact Dovecot:

$ umask 077
$ cat > /tmp/doveadm-save-test.eml <<'EOF'
From: doveadm test <[email protected]>
To: TEST_USER
Subject: doveadm save test 2026-09-23
Date: Wed, 23 Sep 2026 12:00:00 +0000
Message-ID: <[email protected]>

This message was inserted by a controlled doveadm save test.
EOF
$ sed -n '1,12p' /tmp/doveadm-save-test.eml

Replace TEST_USER in the file with the exact Dovecot username before delivery. The .invalid domain stops the example looking like a real sender, but it does not make delivery harmless: Dovecot will still store the message for the selected user.

3. Save one message to INBOX

Use -u to select one user and feed the file in on standard input:

$ TEST_USER='[email protected]'
$ sed -i "s/^To: TEST_USER$/To: $TEST_USER/" /tmp/doveadm-save-test.eml
$ doveadm save -u "$TEST_USER" < /tmp/doveadm-save-test.eml
$ printf 'exit status: %s\n' "$?"
exit status: 0

With no -m, doveadm save stores the message in INBOX. A zero exit status means the command completed successfully. It does not print a message identifier or a delivery receipt.

Sieve is not run for saved messages, while quota is enforced. So this is not a substitute for testing an SMTP submission or a Sieve delivery rule.

4. Target a mailbox explicitly

For a test folder, pass its mailbox name with -m. The mailbox must already be valid for the user in your configuration:

$ TEST_MAILBOX='INBOX/doveadm-tests'
$ doveadm save -u "$TEST_USER" -m "$TEST_MAILBOX" < /tmp/doveadm-save-test.eml
$ printf 'exit status: %s\n' "$?"
exit status: 0

The name is not a filesystem path. Use the same hierarchy and separator that the user's IMAP client shows. If the mailbox does not exist, the command should fail rather than silently create an arbitrary folder. Read the error and correct the mailbox name before trying again.

5. Verify the result without guessing

Open the selected mailbox in an IMAP client and search for the exact subject, or use the Dovecot mailbox tools on your host. A successful save produces one new message with the subject from the file.

Flags, UID and internal dates are assigned by the mailbox backend, so do not assume they match values from another server.

For a command-line check, list the user's mailboxes before and after you choose a destination:

$ doveadm mailbox list -u "$TEST_USER" | grep -F -- 'doveadm-tests'
INBOX/doveadm-tests

The exact listing format depends on the mailbox configuration. If the list is empty, the test folder name is wrong or the account cannot access it. That check does not prove the message was saved. The subject search in the mailbox is the real delivery check.

6. Use a file or all-users mode only with a reason

The command can read a message from a named mail file instead of standard input:

$ doveadm save -u "$TEST_USER" /tmp/doveadm-save-test.eml
 $ printf 'exit status: %s\n' "$?"
exit status: 0

The leading space before printf above is not part of the command; type it without that space. A mail-file argument is a path, while omitting the argument reads standard input. Make the input source obvious in scripts so a pipe cannot be quietly replaced by a terminal or an empty file.

7. Diagnose failures without widening the scope

For extra diagnostics, add the global -v option. Use -D only when you need the extra debug output, because it can expose configuration detail:

$ doveadm -v save -u "$TEST_USER" < /tmp/doveadm-save-test.eml
$ printf 'exit status: %s\n' "$?"
exit status: 0

A failure usually points to the user lookup, mailbox name, permissions, storage availability or quota. Check the exact username and mailbox first.

If the command succeeds but the message is not visible, check that you are looking at the same account and mailbox, let the IMAP client refresh, and search the exact subject. Saved messages bypass Sieve, so a Sieve rule that moves ordinary deliveries is not evidence that this command failed.