-- Chinese spam
-- Big5, GB2312

End users started to receive a lot of Chinese spam messages. What to do to block any Chinese message to pass through the organization?

One efficient way to filter Chinese messages is to create a filter policy based on "charset" parameter in the "Content-Type" message header.

Chinese messages are usually encoded in Big5 or GB2312 character sets. Big5 is used for encoding Traditional Chinese characters and GB2312 is used for encoding Simplified Chinese characters. To create the policy, please follow the steps below:

1. From MG Web Administration UI, go to Mail Policies -> Inbound and click the "Add New" button on the Filter Policies section.
2. Name the policy, e.g. "Filter Chinese character sets".
3. Go to "Headers" IF Condition and select the check mark next to it.
4. From the "MESSAGE CONTAINS:" drop down menu, select "Specific content in the following headers".
5. From the list of standard headers choose "Content-Type".
6. Select the radio button next to "Any of the following" and select "words or phrases" from the drop down list.
7. In the text field on two separate rows, type charset="big5" and charset="gb2312".
8. Select "Next" and whether to Quarantine or Drop messages which violate this policy.
9. Select "Next" and choose the insert position of the policy.
10. Click the "Save" button.

The summary of the policy (if you have chosen the quarantine action) should be as follows:

IF: message headers ('Content-Type') contain: any of the words: 'charset="big5"','charset="gb2312"'
THEN: quarantine message

Please note that this policy will filter messages encoded in big5 and gb2312 character sets. If a message is encoded in "utf-8" character set the policy will not trigger.