EnglishAs I mentioned before, forwarding is the wrong approach. Forwarding is 1990s, today we have Groupware.
You should file it into folders of one or more mailboxes and share that with users. Set the filters to move incoming mails to respective folders. That is done in realtime.
Maybe I do not fully understand your use case. Please bring some examples. And try to be concise. you do not have -email accounts sending to your server, it is email-addresses (as sender-from)
esackbauer Thanks for explaining. Moving into folders and sharing the folder makes totally sense.
Here is my example:
One user should receive (or get access to a folder) e-mails from a list of 2.000 different e-mail addresses. How would you solve that?
My approach: Creating the following filter:
Can I just add for example 2.000 conditions without mailcow and the server facing problems? Or is there a more efficient way?
I canāt set different conditions, as the mails are almost identical. I still need to separate them. The only way to separate them is by āTo or CCā - I was thinking if itās maybe possible to set the value to āemail2 AND email3ā etcā¦ but doesnāt work as well.
dsn receive (or get access to a folder) e-mails from a list of 2.000 different e-mail addresses
I still donāt get it. Is test.de your mailcow mail domain?
What is then the āfrom a list of 2.000 different e-mail addressesā? that would mean sender mail address. Your filter shows then receiving mail addresā¦
What you are explaining sounds like aliasses. Would be aliasses a solution? A user has his main email address associated with his account. And then you can have multiple aliases that he will be also receiving mails for.
esackbauertest@test.de and esackbauertest2@test.de are two of the 2.000 e-mail addresses weāre receiving e-mails.
That was maybe a bad example, because the e-mails would usually look like that, because itās real e-mails from for example web.de. So letās say itās esackbauertest@web.de and esackbauertest2@web.de and we have 5.000 of them that should be accessible by different people.
esackbauertest@web.de and esackbauertest2@web.de forwards to our mailserver then. This is the all in one inbox.
The 2.000 e-mail addresses are receiving newsletter e-mails from e.g. adidas and apple.com.
Aliases is not a solution, because itās web.de and gmx. They donāt support that.
Ok now I understand it. Its 2000 āfromā addresses. However I do not understand what you are doing with all those newsletters 
I would still propose to use a shared folder for this āone inboxā and make this accessible (āfreigebenā as I think you are german) to your internal users.
This way you have only one ruleset in place. Your ruleset above seems wrong, as it is selecting on ātoā instead of āfromā.
You can also have a look at ā+ā addressing, it would automatically create subfolders depending on your alias.
E.g. you have you have ādomain.deā as your mailcow domain. You have a user with āhoneypot@domain.deā as āthe all in oneā mailbox.
So you can use āhoneypot+adidas@domain.deā without any additional effort, and mailcow will automatically create a folder āadidasā and file received mails into that folder. This can then be shared with agent1..n@domain.de.
Sub-addressing - mailcow: dockerized documentation docs.mailcow.email
esackbauer Thanks for the answer.
Iām indeed for germany hahah, good job 
Thatās an incoming mail example and itās āto:ā : 
However, how would you set the rule filter as efficient as possible? Can I just do it like that? 
Sorry, now I am confused again. This is a mail from Costco to a gmail account. What has this to do with mailcow?
are you assuming mailcow is āgmail.comā?
esackbauer Of course not.
Thatās the current setup: nahidhassen992@gmail.com forwards to: mailservicebrand@gmail.com.
mailservicebrand@gmail.com forwards to my mailcow catch-all address.
Thatās why itās under: āto:ā
Now I want to know on how I can set the filter rules as efficient as possible.
Ok, I still do not understand what you want to achieve here. Maybe you can put your use case together so we can better understand why you forward and then forward again. When forwarding is actually bad/old practice.
Forget the forwarding please. Thatās mandatory for us, we canāt change.
Iām just asking on how I can apply the filters the best way possible. can I do the Syntax: āmail1ā AND āmail2ā for example? Or is there any other syntax for this?
Or can I somehow manage the filters differently? For example in a code or with an api?
Do you have a suggestion for this
Thanks already soo much for the help.
Hi.
Are these emails going to a single email account and then you want it forwarded to various people?
Yes -> Using the GUI method above in SOGo will work but will be time consuming. You can instead edit the email addresses sieve filters directly through text and manipulate them that way. However, itās not possible to do this via mailcows GUI. You will need to find an app that can do this. KMail on KDE has this ability.
You -can- use mailcows GUI to create a pre-filter for emails and do this the same way, though.
If the emails are NOT going to a single email address then you will need to make a global pre-filter to do this.
SimplyCorbett Dear Simply Corbett,
Thanks for your help!
What do you mean by: global pre-filter exactly?
Also do you know an alternative to Kmail on KDE for windows where we can efficiently manage rule filters?
I have seen something like directly modifying the .sieve files inside the mailserver itself.
Is there a good way on how to do it? And does this even make sense?
Like with an external e-mail client or something.
dsn There is an option in the mailcow admin UI called āglobal pre-filterā which is a text field you can edit.
As mentioned, you can also modify the users server-side sieve filters directly with a mail client such as KMail.
SimplyCorbett Awesome, thanks!
I didnāt know you mean sieve filters with the KMail client. Do you know a KMail alternative that works for windows as well?
I donāt use windows.
dsn Not a desktop client, but Roundcube has a Sieve clinet where you can create rules graphically. You can either install it directly on your Mailcow server, or on any server with a LAMP stack, or in theory even on your desktop computer (preferably in a Linux VM).
Roundcube - mailcow: dockerized documentation docs.mailcow.email
