The Spamhaus Composite Snowshoe (CSS) blocklist uses proprietary data to identify IPs with low reputations that send snowshoe spam, or spam from compromised hosts. This blocklist is a component of the Spamhaus Block List (SBL).
- Listings occur at the IP level.
- The impact on deliverability is low.
Reasons for getting listed
IP addresses are listed for:
- Sending email to Spamhaus spam traps
- Deploying email from IP addresses across several different IP ranges or netblocks at a low volume
- Sending email from a compromised system
- Other indicators of low reputation or abuse as defined by Spamhaus
How to get off this blocklist
Removal is at the discretion of the Spamhaus team but usually occurs automatically 48 hours after the last receipt of spam.
You can request removal using the IP and domain reputation checker, but it is important you resolve the root cause of the listing before making the request. If you do not do this, future listings will be harder to get removed.
Multiple Spamhaus CSS listings may cause the IP to be listed on the Spamhaus Block List (SBL), which can cause serious deliverability problems.
Tips for staying off this list
- Avoid changing sending IP addresses when you encounter delivery problems
- Use confirmed opt-in
- Grow your subscriber list organically with tactics such as website sign ups, SEO, and point of sale sign ups
- Do not purchase or rent lists, or use other risky acquisition methods
- Conduct ongoing list maintenance and list hygiene
- Implement proper security measures to ensure your systems are not used to send spam from an unauthorized third party