Hi,

Could someone tell me the best way to allow postfix to reject a specific file attachment i.e. 'delivery_information.zip' and not just a wildcard extension ?

Thanks Simon.

See the following link: http://www.cyberciti.biz/tips/postfix-block-mime-attachment-files.html

Note in the instructions, the line that says: /name=[^>]*\.(bat|com|exe|dll|vbs)/ REJECT

In case you are not familiar with the concept, this is what is called a regular expression which is a pattern matching language.  If I remember my regex syntax correctly it says to match "name equals zero or more characters that are not > followed by a . followed by bat or com or exe or dll or vbs.  On a match, the rule is to reject the file.

In your case, you should be able to substitute the wild card match for the explicit file name.  In other words, use
/name=delivery_information.zip/ REJECT