Reject Tickets with Subject "-"


is it possible to have an exact Match here and not “contains”? I want to send an Email back to the Customer when the Subject is “-”.

Postmaster filters have regex support. That would allow you to do certain things to the ticket during its creation to then fire a trigger based on that.

Hi. Thank you, but i dont find any Regex Option there:

How can i solve that?

It’s all in the docs:

You’ll have to use the right syntax.


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Well, i tried it with Regex but Tickets are still created when Subject is -

Subject contains: regex:/^-$/
Ignore Message: yes

Am i using it wrong?

We have following set up that works:

just change the action to whatever you want to do with it

subject does not contain: regex:(.\S.)

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Hi. Thank you. Whats does your Regex do? I’m not really into Regex

The regex matches anything that matches more than just being a whitespace.

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So, what do you do with such Mails? Is there a way to reject and answer?

We use a trigger that checks for the added tag.
It then sends a reply to the customer/user that his email was rejected and closes the ticket.


i tried your regex and i cant see that it works. A Mail with empty Subject will not be tagged and so my Trigger doesnt will not be triggered. My Regex for the “-” works fine.

Could it be posible that Mails with empty Subject are changed by the System? I can see that empty Subject are presented as “”

Do i need my regex filter to look for “”?




i added an E-Mail Filter:

but an incomming Email with “-” as Subject will not be tagged.

Where is my fault here?



The fault is that Zammad adds the - during ticket creation not during the evaluation of the mail subject.
During the postmaster filter check the subject still should be “empty”.

So this should never ever work this way? How could that be, that @matsc-h 's solution is working for him. And i think it worked 2 or 3 time for me too. But now it is no longer tagging those Tickets.

I am still looking for a way to reject emails with the subject “-” and return a reply. What can I do?

Regards and many thanks.


The issue is not that the mail contains - but that the original mails subject is in fact empty.
You could reject / drop those kind of emails on email server side.

The filter @matsc-h suggested does work, but in my test filters slithgly more like also . subjects.
I couldn’t find a more stable way and gave up after investing 20 minutes with fiddling.

What I can tell:
- subjects are not evaluated. This means the filter indeed runs before the sign is being added to the ticket title. Hopefully this helps at least a bit.

Thank you for your help!

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