How do I block non-English spam?

If non-English spam written using non-English character sets is getting past Postini spam filters, you can create Content Manager filtering rules to block these messages. The rules can be written to scan the Internet message header where character encoding instructions are passed with the e-mail message.

For example, to stop Russian spam (written in a Cyrillic character set), an effective Content Manager filter rule would be:

Rule Name: Non_English_spam
"Match Any"
Header - matches regex

koi8-r|koi8-u|koi7
Disposition: delete (blackhole)
Set quarantine to Recipient

This will quarantine all messages with any of the three characters sets in the recipients quarantine.

Important: Use caution when setting Content Manager rules. And errors when the rule is set to Blackhole will cause you to lose email. Always use a a quarantine address when first setting up Content Manager rules to test that they are functioning correctly before you set the disposition (routing) to Blackhole.

See also the following:

Content Manager: http://www.postini.com/webdocs/admin_ee_cu/cm_create_filter.html

Character sets: http://en.wikipedia.org/wiki/Character_encoding

Note: A Japanese character set is ISO-2022-JP


For a checklist of security best practices and links to other important resources for your service, visit Postini Security Central.