Add the TLD to the Local Bad Sender Domains. (Reputation -> Bad Senders -> Local Bad Sender Domains)
Use the format *.tld (with the * being a wildcard)
You can create a content filtering rule that will allow you more flexibility.
It will allow you to create exceptions to the rule or specify a policy group for the rule to apply.
- Create a dictionary (Content -> Dictionaries -> Add)
- Name the dictionary (i.e. Blocked TLD's)
- Enter a TLD and click Add (Repeat as needed.) Click Save when finished.
- Click Content on the top menu bar.
- Click Add to create a new content rule.
- Click select to start with a blank rule.
- Name the policy (i.e. Block TLD's)
- Under Conditions, change apply to to inbound messages.
- Under Conditions, click Add.
- Select "Text in the specific part of the message header" and select Envelope Sender in the drop-down to the right. Change "Email address" to "Country code". Select the dictionary you created in step 1. (i.e. Blocked TLD's) Click Add Condition.
- Configure an action under Actions.
- Select groups to apply the rule to under "Apply to the following policy groups" Click Save.