Use a SpamExperts sender block entry for repeated unwanted mail from a known address or domain. First distinguish the sender you want to block from the local recipient who is receiving the messages.
IN THIS ARTICLE
01 Add and verify the block
- Inspect an unwanted original message and identify the sender address you intend to match.
- Open Incoming - Protection Settings > Sender Block list. Use the intended email or domain scope, then choose Block sender. An administrator-wide entry affects all domains under that administrator.
- Where shown, select the receiving domain and recipient local-part. Choose whether to match the envelope sender, the message From address or both.
- Enter the specific sender in Address and save. A whole-domain entry is just the domain, without an @ or wildcard. Record why the entry exists.
- Check subsequent logs for the intended action and verify unrelated business messages still arrive.
An envelope-sender match normally rejects the SMTP transaction before the message is accepted, so it does not create a quarantine copy by default. A From-header match treats the message as spam under the configured action. If both are selected, the matching stage determines which handling occurs first.
02 Review the impact
Blocking an entire public mail provider can exclude many legitimate customers. A compromised supplier account may also require direct communication with that supplier, not just a permanent block. Use message reporting to help classify the unwanted content.
Common questions
Should I use Recipient Block list?
That blocks mail sent to the selected local recipient. It is a different action and can stop that employee's legitimate incoming mail. Use the sender control for an unwanted source.
Can I block spoofing by blocking my own domain?
Do not broadly block your own domain for that purpose. It can interfere with legitimate internal or application mail. Review authentication and the actual route instead.
What if spam keeps arriving with new addresses?
A list of individual blocks may not solve a changing campaign. Report representative original messages and investigate common content or routing evidence with the authorised administrator.
Remove a mistaken block promptly, then ask affected senders to resend messages that were rejected. Deleting the rule does not necessarily recover earlier mail. Keep a record of the change and its test so another administrator can understand why the previous entry was removed.