(How to) Roundcube e-mail filter to remove e-mails with attachments

[vvenet]

Dear Support Team,

How to setup a filter in Roundcube, that will detect and delete incoming e-mails with a ".gz" attachment?
Some backgroud: I am experiencing annoying incoming fake e-mails which all have an attachments with a " *.gz " extension.

I know it can be done, but how? I used Google to find answers. One solution I found is here: https://jensknipper.de/blog/roundcube-sieve-filter-attachments/ , but I do not know how to implement it. (In this solution a zip-file is mentioned; in my case it is about a gz-file.)

I hope you can give me the proper instructions how to do setup a filter in Roundcube who will detect and delete incoming e-mails with a ".gz" attachment.

Kindly awaiting your reply. 🙂

[vvenet]

On 8/12/2025 at 10:58 AM, vvenet said:

Dear Support Team,

How to setup a filter in Roundcube, that will detect and delete incoming e-mails with a ".gz" attachment?
Some backgroud: I am experiencing annoying incoming fake e-mails which all have an attachments with a " *.gz " extension.

I know it can be done, but how? I used Google to find answers. One solution I found is here: https://jensknipper.de/blog/roundcube-sieve-filter-attachments/ , but I do not know how to implement it. (In this solution a zip-file is mentioned; in my case it is about a gz-file.)

I hope you can give me the proper instructions how to do setup a filter in Roundcube who will detect and delete incoming e-mails with a ".gz" attachment.

Kindly awaiting your reply. 🙂

Dear @wolstech Can someone please have a look at my question? It is open since August 12. Kind regards. 

[wolstech]

I suspect you didn't get a response because nobody here knows how to do this. I've never really used Roundcube for much beyond testing mailboxes. I use Gmail as a front end to check my HH emails instead. On Gmail, doing this is as simple as creating a filter with the criteria "filename:gz" and specifying what to do with the messages.

Based on the link you gave, you could probably change the content-type field to application/gzip (or possibly application/x-gzip) to make it look for .gz instead of regular zip. I've never used sieve though (and honestly I'm not sure the Plesk Roundcube even supports it).