So the issue is that i have been trying to send a mail from my server with xlsx file extension attachment but zimbra rejects the mail giving a message content is band


Our content checker found
    banned name: .asc,docProps/app.xml

in an email to you from:

And same time another mail arrives in the inbox which looks like this:

No viruses were found.

Banned name: .asc,docProps/app.xml
Content type: Banned
Internal reference code for the message is 21005-02/Sppi_Gv8AtCP

First upstream SMTP client IP address:

I have checked in the admin console > configuration> global settings > attachments > currently blocked extension

But xlsx is not listed there

So are there any solutions

  • From the messages, it seems the blocked contents are .asc, .xml and not xlsx file. please check if there are any .asc, .xml files included. Jul 13, 2021 at 8:01

1 Answer 1


You may not be blocking xlsx directly - but amavis is perfectly capable of noticing that xlsx files are zip format archives, and inside that attachment there can be a file named docProps/app.xml which in turn can be blocked based on its file extension.

I do not know whether zimbra allows you any separate configuration to configure different rules for nested filenames than for file names mentioned directly in the MIME structure.

Carefully investigate whether you want to allow filenames like those commonly contained in xlsx files.

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