Personal Sieve filters in SOGo webmail

Personal Sieve filters are filter rules that apply only to your mailbox and that you create directly in SOGo webmail. With them you can sort mail automatically, flag senders, filter out newsletters or set up an out-of-office notice.

These filters run server-side — mail gets sorted even when your mail client isn’t open. Outlook or Apple Mail rules, by contrast, only work inside that one client.

Opening the filter section

In SOGo:

1. Top right, click your profile picture → Settings.
2. Filters tab.

You see a list of your active filters. Empty by default.

Creating your first filter

Click New filter.

In the filter editor:

• Name: a descriptive label (e.g. “Sort newsletters”)
• Conditions: what should match
• Actions: what should happen

Conditions

Each condition has:

Element	Example
Field	From, To, Cc, Subject, Body, any mail header
Operator	contains / is equal to / matches pattern
Value	”newsletter@” or “[Invoice]”

You combine multiple conditions with “AND” or “OR”.

Actions

What should happen to the matching mail:

• Move to folder: into “Newsletters”, “Invoices”, “Spam”
• Forward to: another mail address
• Forward a copy: original stays in the mailbox + copy goes to the other address
• Discard: mail goes into the shredder (not into Trash — gone completely)
• Flag: red flag, read, unread
• Stop: abort filtering, no further filters run

Example filters we see a lot

1. Sort newsletters

Condition	Value
From contains	@newsletter.de OR newsletter@firma-x.com

Action: move to folder “Newsletters”.

That gets all the newsletter noise out of your inbox.

2. Flag invoices

Condition	Value
Subject contains	[Rechnung] OR Rechnung Nr.

Action: move to folder “Invoices” + flag.

3. Mail from an important sender always in the inbox

Condition	Value
From is	chef@firma.de

Action: stop.

With stop as the only action, no later filters (spam sorting, for instance) get a chance to run — important mail is guaranteed to arrive in the inbox.

4. Sorting based on spam score

Condition	Value
Header X-Spamd-Score greater than	8

Action: move to folder “Junk”.

Mailcow has its own spam filter that assigns each mail a score. With this rule you move very-spammy mail into Junk without touching legitimate mail (score < 8).

5. Aliases into their own folders

Condition	Value
To contains	info@deinverein.de

Action: move to folder “Info mail”.

If you’ve pointed info@ as an alias at your main mailbox, this separates the info mail from your personal mail.

Out-of-office notice / auto-reply

Special case: in Settings → Vacation you set up an automatic reply.

Fields:

• Check Enabled
• Date from / until: if you’re only away during a specific period
• Subject: for the auto-reply mail
• Message: your out-of-office text

From our experience, a good auto-reply text:

Thanks for your mail.

I'm out of office from July 15 to July 31, 2026.
For urgent matters, please contact kollegin@deinverein.de.

I'll be back on August 1 and will reply promptly.

Best regards
Firstname

Careful: every mail to your mailbox gets an auto-reply, newsletters included. SOGo prevents endless loops with other auto-reply systems, but with lots of incoming newsletters the newsletter providers receive lots of auto-replies — so write a useful text, not just “I’m on vacation”.

Testing filters

SOGo has no built-in filter tester. Best practice:

1. Create the filter.
2. Send yourself a test mail the filter should catch.
3. Check whether the mail lands in the right folder.

On syntax errors, SOGo refuses to save outright.

Filter order

If you have multiple filters, every mail runs through all of them — in the order of the list. The first matching action wins.

You can change the order via drag and drop in the filter list.

Important: filters with stop abort processing. If a filter puts important mail safely into the inbox + stop, later filters no longer run.

Best practices

Start with few filters. 3–5 filters cover most mailboxes. More gets confusing, and unused filters are technical debt.

Discard is final. With discard the mail is gone — no way back. Better: fileinto "Suspects" and skim through it once a week.

Review filters regularly. Newsletter domains change, senders change. Go through your filters once a quarter — what still matches, what doesn’t?

Build the auto-reply with dates. Instead of manually enabling and disabling, enter the date range in the auto-reply. SOGo switches automatically.

Frequently asked questions

What’s the difference to mail-client filters? Sieve filters run on the server — even when your mail client is off. Mail-client filters (Outlook rules, Thunderbird filters) only run while the client is open. Server filters are more robust; client filters have more options (such as “move to trash with a delay”).

Can I write Sieve scripts directly? Not in SOGo webmail — it only shows a GUI filter editor. If you have pro-grade Sieve scripts, you can upload them via IMAP Sieve tools (such as pysieved or the Sieve Editor in Thunderbird).

How many filters are allowed? Practically unlimited. Performance-wise things slow down at 50+ filters — but we’ve rarely seen mailboxes with that many.

Do filters apply to mail already received? By default no — Sieve filters act on newly incoming mail. For mail already received, you can apply them manually once (“Run filters now”) or use SOGo’s sorting function.

What happens if I set a filter with discard and a typo makes it hit the wrong mail? The mail is gone, not recoverable. So: better fileinto "Test-Discard" for a week of testing, only then discard.

Can I use filters across domains? Personal filters apply only to your mailbox. Domain-wide filters are set by the domain admin in the Mailcow GUI — see Domain-wide Sieve filters.

What if the auto-reply doesn’t work? Frequent causes: date range wrong (start after end), auto-reply configured for internal mail only (check the checkbox), or Mailcow hasn’t activated the auto-reply (check the mail log).

What’s next

• SOGo webmail — first login and overview
• Understanding spam and junk
• Domain-wide Sieve filters