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Barracuda (Email Protection and Email Security Gateway) · permanent error

554: no reverse DNS for the sending IP

Your sending IP has no reverse DNS (PTR) record, and the recipient’s Barracuda gateway is set to refuse servers without one.

Barracuda
Provider
Permanent (5xx)
Class
Sources checked
By , email deliverability consultant
Author

At a glance

Code
554
Temporary or permanent
PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
Who has to act
The sender. The fix is on the sending side: your domain, your server or your list.
What the server says
554 IP name lookup failed. No PTR record found for the given IP address.

What it means

Every legitimate mail server is expected to have a PTR record, so that looking up its IP returns a host name. Barracuda gateways can require one, and this reply means the lookup for your server’s IP found nothing. The rejection is permanent. The PTR record is set by whoever controls the IP address, usually your hosting provider or ISP, not in your domain’s own DNS zone. The host name it returns should also resolve back to the same IP, and your server should announce that name in HELO.

Common causes

  • A new server or VPS whose provider has not set a PTR record.
  • Mail sent directly from a home or office connection instead of a mail server.
  • The IP changed and the new one has no PTR record.

How to fix it

  1. 01Look up the PTR record of your sending IP.
  2. 02Ask your hosting provider or ISP to set it to your mail server’s host name, or set it in their control panel.
  3. 03Make sure that host name has an A record pointing back to the same IP.
  4. 04Resend once the PTR record resolves.

Sources

What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.

  1. 554Transaction failed.The server permanently refused the transaction, often after receiving the message data or straight away when the connection opened.StandardPermanent

554 at other providers

  1. 554Permanent rejection (554).Yahoo or AOL rejected the message for good with a 554. Yahoo uses this code for several problems, from failed authentication to unacceptable content, so the wording of the reply tells you which.YahooPermanent
  2. 554Failed authentication.Yahoo or AOL refused the message because it failed the checks that confirm the sending domain, such as DKIM against the domain's policy. Yahoo lists this among its permanent 553 and 554 errors.YahooPermanent
  3. 554Recipient does not exist.The Yahoo or AOL account you wrote to does not exist. The failure is permanent: check the address with the recipient, and remove it from any list.YahooPermanent
  4. 554No reverse DNS (PTR) record.Xfinity refused the connection because your sending IP has no PTR record. Every server sending to Xfinity needs valid reverse DNS, so the owner of the IP must add one.ComcastPermanent
  5. 554Rejected for breaking GMX guidelines.GMX refused the message permanently because the connection broke its guidelines. GMX points to its requirements page and asks for the full error message if the problem continues.GMX, WEB.DEPermanent
  6. 554IP address on the GMX blocklist.Your sending IP is on a blocklist that GMX manages itself, so its servers refuse the connection. GMX keeps a strict no tolerance policy toward spam.GMX, WEB.DEPermanent

Further reading

All 11 Barracuda codesEvery code in the wikiPaste your own bounce

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