The Cloudmark CSI blocklist is owned an operated by Proofpoint. It uses a combination of techniques to identify possible sources of spam using data from the Cloudmark Global Threat Network.
- Listings occur at the IP level.
- The impact on deliverability is high.
Reasons for getting listed
Your IP address may be listed if:
- You use a shared IP address and either you or another company using the IP address is sending spam.
- Your sending system was compromised by a third-party to send spam.
- Your sending practices result in a high number of subscribers reporting your email as spam.
How to get off this blocklist
This blocklist accepts manual requests to remove IP addresses. Submit a delisting request using the remediation form. Prior to submitting your request, it is recommended to fix the cause of the listing or future delisting requests may be ignored.
If you are a Proofpoint Essential customer, fix the cause of the listing and follow Proofpoint's delisting procedure.
Tips for staying off this blocklist
- Confirm that your IPs have PTR records in DNS that resolve to a valid hostname.
- Make sure your servers are properly configured and have no open relays or open proxies.
- Conduct ongoing security checks to prevent unknown third-parties from sending spam.
- Use a dedicated IP address.
- Use opt-in consent methods to obtain subscribers.
- Maintain good list hygiene practices and regularly remove unknown or invalid subscribers.
- Send relevant and timely email to encourage high subscriber engagement.
- Ensure your IPs are signed up for all available complaint feedback loops and suppress subscribers that report your email as spam.