Email Content Filtering

Email can be filtered for unwanted attachments and content.

Filename filtering includes options to:

• Strip attachments with dangerous filename extensions
  There is a default list of file types that can be allowed or denied. This list can be added to using regular expressions.
• Strip attachments with very long filenames ( >150 chars)
• Strip if a Filename contains lots of white space

Content filtering includes many options that are enabled by default.

• Block Partial messages
  Partial messages only contain a fraction of attachments, not the whole thing. There is absolutely no way to scan these 'partial messages' properly for viruses, as the entire the attachment isn't seen. This option stops viruses getting through.
• Block External message bodies
  Blocks messages whose body is stored somewhere else on the internet, which is downloaded separately by the user's email package. There is no way to guarantee that the file fetched by the user's email package is free from viruses. (Only currently supported by Netscape 6 anyway, and the only people who use it are the IETF.)
• Block encrypted messages
  This is useful if you are wary about your users sending encrypted messages to your competition.
• Allow Password-Protected files in Archives
  Should archives which contain any password-protected files be allowed? Leaving this set to 'no' is a good way of protecting against all the protected zip files used by viruses at the moment.
• Disarm IFRAME Tags
  Protects you against various Microsoft Outlook security vulnerabilities.
• Disarm FORM Tags
  Prevents scams trying to persuade people to part with credit card information and other personal data
• Disarm SCRIPT Tags
  Protects against vulnerabilities in email applications and web browsers.
• Disarm CODEBASE Tags
  Protects against various Microsoft-specific security vulnerabilities..
• Disarm WebBugs
  Stops 'web bugs' used to find out if an email message has been read. It is not dangerous, it is just used to make you give away information. You may not want this.
• Convert ALL HTML to text