I found this little article the other day while looking for ways to block all that fucking virus shit thats being sent around..
blocking mime types seems pretty easy.. here is an insert from the web page on how do to it. not this is for postfix 2.x
Generic solution: mime_header_checks (Postfix-2.x only!)
The generic solution is to disallow certain known to be dangerous attachment types. Basically, this is everything Microsoft invented. In main.cf you must use:
mime_header_checks = regexp:/etc/postfix/mime_header_checks.regexp
And /etc/postfix/mime_header_checks.regexp (download it here) contains:
/filename=\"?(.*)\.(bat|chm|cmd|com|do|exe|hta|jse| rm|scr|pif|vbe|vbs|vxd|xl)\"?$/
REJECT For security reasons we reject attachments of this type
Georg Gell recommends that you could also use:
mime_header_checks = regexp:/etc/postfix/mime_header_checks.regexp
and /etc/postfix/mime_header_checks.regexp (download it here) contains:
/^\s*Content-(Disposition|Type).*name\s*=\s*"?(.+\.(lnk|asd|hlp |ocx|reg|bat|c[ho]m|cmd|exe|dll|vxd|pif|scr|hta|jse?|sh[mbs]|vb[esx]|ws[fh]|wav|mov|wmf|xl))"?\s*$/
REJECT Attachment type not allowed. File "$2" has the unacceptable extension "$3"
The leading spaces before REJECT are important in both cases!
Don't forget "postfix reload"!
this really helped alot..
more from the site here:
http://sbserv.stahl.bau.tu-bs.de/~hi...x_sobigf.shtml