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Error code wiki · 7 codes

Cisco Secure Email SMTP error codes

Cisco Secure Email Gateway, long known as IronPort, filters incoming mail for businesses on site or in Cisco’s cloud, using sender reputation data from Cisco Talos.

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Permanent failures (5xx)

4 codes

The receiving server refused the message for good. Your server will not try again, and the message comes back to you as a bounce.

  1. 550Too many invalid recipients (harvest protection).Your server tried too many addresses that do not exist at this company within an hour, so the Cisco gateway’s harvest protection is refusing it.Permanent
  2. 550 5.7.1SPF check failed.The recipient’s Cisco Secure Email gateway checked SPF, found your server not authorised for the sender domain, and its policy rejects that result.Permanent
  3. 550 5.7.1Rejected under your domain’s DMARC policy.Your message failed DMARC, your domain’s DMARC record asks receivers to reject such mail, and the recipient’s Cisco gateway did so.Permanent
  4. 550 5.7.1DMARC verification failed permanently.The Cisco gateway hit a permanent failure while verifying DMARC for your message, and the recipient’s policy rejects such mail. Cisco does not say what produces that failure.Permanent

Temporary failures (4xx)

3 codes

The receiving server cannot take the message now. Your server keeps it and retries, and only bounces it if the retries run out.

  1. 451 4.4.3SPF could not be checked.The Cisco gateway could not complete an SPF check for your domain because of a temporary error, usually in DNS, and asked your server to retry.Temporary
  2. 451 4.7.1DMARC could not be checked.A temporary failure stopped the Cisco gateway from verifying DMARC for your message, and its policy defers such mail, so your server should retry.Temporary
  3. 452Hourly recipient limit reached.Your server sent more recipients to the company’s Cisco gateway this hour than its rate limit allows. The rest are deferred until the limit resets.Temporary

Every code in the wikiPaste your own bounce

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