Blocking custom file extension is not working

Kevin Miller kevin.miller at
Fri Feb 5 17:30:50 UTC 2016

That's because Windows determines file types based on the extension.  Outlook sees .dll so figures "hmm, must be true".  Linux uses the file command to determine what type of file it is, so recognizes that it isn't really a .dll.

MailScanner blocks on both filetype and filename - just add a new line in filename.rules.conf and you're set.  I'd copy an existing line and edit to suit.

Kevin Miller
Network/email Administrator, CBJ MIS Dept.
155 South Seward Street
Juneau, Alaska 99801
Phone: (907) 586-0242, Fax: (907) 586-4500 Registered Linux User No: 307357

From: MailScanner [mailto:mailscanner-bounces at] On Behalf Of Pieter Goris
Sent: Friday, February 05, 2016 5:13 AM
To: mailscanner at
Subject: RE: Blocking custom file extension is not working


But the file is shown in outlook as a .dll
So is there a way to block this?

Pieter Goris

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