What is SpamRats and its specialized lists?

If your IP address is missing a PTR record or comes from a residential range, SpamRats will list it. That's really the core of what this blocklist does. Unlike general-purpose blocklists that focus on complaint volume or spam trap hits, SpamRats is almost entirely focused on infrastructure problems.

SpamRats runs four zones, and each targets a different type of sending problem:

• dyna.spamrats.com. Dynamic and residential IP ranges. These shouldn't be sending email directly, and SpamRats flags them when they do.
• noptr.spamrats.com. IPs with a missing or invalid reverse DNS record. If your sending IP doesn't have a PTR entry, this is where you'll land.
• spam.spamrats.com. IPs caught sending to SpamRats honeypots. This one is earned the old-fashioned way.
• all.spamrats.com. A combined zone that queries all three at once.

The practical impact is relatively low. SpamRats listings carry weight mostly in Spamhaus-adjacent configurations and SpamAssassin setups. Major inbox providers don't lean heavily on SpamRats, but smaller mail servers and some hosting environments do check it.

What gets you listed and how to get off:

• Dyna listing: Your IP is classified as dynamic or residential. The fix is switching to a static IP and ensuring it's registered correctly with your ISP or hosting provider.
• NoPtr listing: Your IP has no reverse DNS. Set up a PTR record pointing to your sending hostname. Once it resolves cleanly, you can request removal.
• Spam listing: You've hit their traps. Stop whatever triggered it, wait for automatic expiry, or submit a manual review request at spamrats.com/lookup.php.

If you want to check whether your sending IP shows up on SpamRats or any other blocklist, our free Blocklist Checker covers the major lists in one shot.