# Flooding filter (DCL)

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The flooding filter also called DCL (Destination Counter Limitator) is a platform-level security mechanism. It protects both end subscribers and Infobip clients from accidentally sending a large number of messages to the same destination number. By default DCL applies to outbound SMS and is enabled for every account.

A message rejected by the filter gets the [`REJECTED_FLOODING_FILTER`](https://www.infobip.com/docs/developer-resources/api-fundamentals/message-status-codes#rejected-general-general-status-codes) status with the [`EC_DESTINATION_FLOODING` or `EC_DESTINATION_TXT_FLOODING`](https://www.infobip.com/docs/developer-resources/api-fundamentals/error-code-reference#user-errors-general-general-error-codes) error code. Unlike API-level throttling the API request still succeeds the rejection shows in the delivery report and message logs not as an HTTP `429` Rejected messages are not charged.

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## Default thresholds

The following table lists the default thresholds:

| Content | Limit | Rejected from | Error code |
| --- | --- | --- | --- |
| Identical content | 6 messages within 60 minutes | The seventh message | 4104 `EC_DESTINATION_TXT_FLOODING` |
| Different content | 20 messages within 60 minutes | The 21st message | 4103 `EC_DESTINATION_FLOODING` |

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## Impact on integrations

When building or testing integrations be aware of the following:

- Sending the same OTP or test message more than 6 times within 60 minutes to the same number triggers DCL.
- Retry logic that resends identical content can silently exhaust the threshold See [Retry safely](https://www.infobip.com/docs/developer-resources/api-fundamentals/handling-errors#retry-safely).
- Rejected messages also count toward the limit With the default settings stop sending to that number for 60 minutes to clear it.
- By default DCL counts messages per destination number on your account regardless of the sender DCL is set separately for each sub-account.
- To exclude a test number from DCL ask your account manager or [Support](https://www.infobip.com/contact) to safelist the number.

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## Adjust or disable the filter

To adjust or disable the flooding filter contact your account manager or [Support](https://www.infobip.com/contact). You can ask for different limits a different time window or a rule for a specific country or sender. Keep the filter enabled for most use cases The default thresholds protect against both accidental loops and fraudulent use of your account.

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Related pages

[Rate limits and throttling](https://www.infobip.com/docs/developer-resources/api-fundamentals/rate-limits-and-throttling)
How rate limits and throttling work and how to handle 429 responses with retry logic.

[Handling errors](https://www.infobip.com/docs/developer-resources/api-fundamentals/handling-errors)
How Infobip APIs report request errors and delivery error codes and how to retry failed requests.

[Go live checklist](https://www.infobip.com/docs/get-started/build-and-go-live/go-live)
Move from the free trial to production traffic including a check of the flooding filter.

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