How to remove your IP from SpamRats Dyna

RATS-Dyna is not a spam list — it is a reverse-DNS list. Fix the PTR record and the listing clears.

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What it is

The list, in plain terms.

RATS-Dyna is one of several DNS blocklists published by SpamRats (operated by mThreat Technology Inc.) in the zone dyna.spamrats.com. It lists IP addresses whose reverse DNS looks dynamic, residential or automatically generated — the kind of PTR record an ISP hands out to broadband and mobile customers rather than to a mail server.

The premise is that such addresses should not be delivering mail directly to recipient MX servers. Legitimate senders on those ranges are expected to relay outbound mail through their provider's authenticated submission server. An IP earns a Dyna listing when it connects direct-to-MX from that kind of space, often alongside abusive patterns such as attempts to deliver to invalid recipients.

This is a policy and configuration listing, not an accusation of spam. It is consulted by a moderate number of receivers rather than the majority, but a listing can still cause deferrals or rejections until the reverse DNS is corrected.

Why you get listed

What a listing on SpamRats Dyna means.

Dynamic or generic reverse DNS The PTR record for the IP matches patterns SpamRats reads as dynamically assigned or residential — for example hostnames containing the IP octets, or ISP-generic names — rather than a proper mail-server hostname.

Direct-to-MX from the wrong space Mail was sent straight to recipient mail servers from an IP that, by its reverse DNS, should be routing outbound mail through an ISP or provider relay instead.

Missing or mismatched PTR The IP has no reverse DNS, or the PTR does not forward-confirm (the hostname does not resolve back to the same IP), so it cannot be distinguished from throwaway dynamic space.

Abusive connection behaviour Connections from the IP show characteristics SpamRats associates with compromised or misconfigured hosts, such as high volumes of attempts to deliver to non-existent addresses.

How to get removed

Delisting, in order.

Removal is free. Fix the cause first — a listing you clear without a fix comes straight back.

1 Confirm the listing and the zone. Look the sending IP up with the SpamRats lookup tool. Check that it is RATS-Dyna specifically (return code 127.0.0.36) and not one of the sibling zones, because the fix here is reverse DNS rather than list hygiene.
2 Set a proper reverse DNS record. This is the actual fix. Give the IP a PTR record that names a real mail-server hostname (for example mail.yourdomain.com) conforming to best practice for email and network operators — not a generic or dynamic-looking name. Reverse DNS is set by whoever controls the IP block, so ask your ISP or hosting provider if you do not manage it yourself.
3 Make the DNS forward-confirm. Ensure the hostname in the PTR resolves forward (A/AAAA) back to the same IP, giving valid FCrDNS. Add SPF, DKIM and DMARC while you are here so the sending setup reads as a legitimate mail server.
4 Wait for DNS to propagate. Allow the new reverse DNS to propagate before requesting removal — this can take up to 48 hours. Removing before the PTR is visible and correct will only lead to a re-listing.
5 Submit the removal request. Request delisting at the SpamRats removal page. Removal is only granted once the reverse DNS conforms to best practice, so state what you corrected. The request is free.
6 Re-check before resuming. Confirm the IP no longer returns 127.0.0.36 in the SpamRats lookup before you ramp sending back up.

The official route

Straight to the source.

Removal happens on SpamRats Dyna's own tool — never through a paid service.

SpamRats Dyna removal tool ↗

Return codes

127.0.0.36 RATS-Dyna — dynamic or generic reverse DNS sending direct to MX

127.0.0.37 RATS-NoPtr — no reverse DNS at all (separate SpamRats zone)

127.0.0.38 RATS-Spam — known spam source (separate SpamRats zone)

How long it takes

Once the corrected reverse DNS has propagated — allow up to 48 hours — a removal request is reviewed and processed by SpamRats. There is no fixed guaranteed turnaround. If the PTR is not fixed first, the IP is simply re-listed, so the reverse DNS change is what determines whether removal sticks.

Common questions

About SpamRats Dyna, specifically.

Does SpamRats charge to remove my IP from RATS-Dyna? No. Removal is free at the SpamRats removal page. Any service offering to clear a SpamRats listing for a fee is a scam — no third party can influence a SpamRats removal.

Why is my IP on RATS-Dyna if I never sent spam? RATS-Dyna is not a spam list. It flags IPs whose reverse DNS looks dynamic, residential or auto-generated and which send mail directly to MX servers. The trigger is your PTR record and how you route mail, not message content.

How do I actually get off RATS-Dyna? Set a proper reverse DNS (PTR) record naming a real mail-server hostname that forward-confirms to the same IP, let it propagate, then submit a removal request. Fixing the PTR is the fix; the request without it will not hold.

I do not control the reverse DNS — what do I do? Reverse DNS for an IP is set by the ISP or hosting provider that owns the address block. Ask them to point the PTR at your mail-server hostname, or send outbound mail through their authenticated relay instead of direct-to-MX.

How long does RATS-Dyna delisting take? Budget up to 48 hours for the corrected reverse DNS to propagate, then time for SpamRats to review the request. There is no fixed guaranteed timeframe.

How much does a RATS-Dyna listing hurt deliverability? RATS-Dyna is consulted by a moderate set of receivers rather than most, and major providers weight it lightly. It can still cause deferrals or rejections at the receivers that use it, so fix the reverse DNS rather than ignore it.

The bounce behind the listing.

554 5.7.1 message rejected → The permanent bounce a listing most often triggers — what it means and how to clear it. 550 5.7.1 blocked → A rejection on reputation grounds — usually the same listing, seen from the sender side. Blacklist checker → Re-check your domain and every sending IP once the cause is fixed.

Do not fix it blind.

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