> Source: [sk104637](https://support.checkpoint.com/results/sk/sk104637)

# sk104637 - IPS protection "TCP Off-Path Sequence Inference" drops TCP packets originated by Security Gateway

| Property | Value |
|----------|-------|
| Solution ID | sk104637 |
| Date Created | 2015-02-09 |
| Last Modified | 2015-05-30 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- * SmartView Tracker logs show that IPS protection "TCP Off-Path Sequence Inference" drops TCP packets originated by Security Gateway:

  ```
  
  Blade: IPS
  Action: Drop
  Attack Name: Streaming Engine: TCP off-path sequence inference
  Attack Information: TCP off-path sequence inference.
  Protection Name: TCP off-path sequence inference
  Protection ID: tcp_off_path_enable
  ```

* SecureXL status (enabled / disabled) is not relevant.

## Cause

IPS protection "TCP Off-Path Sequence Inference" drops TCP packets originated by Security Gateway that contain "ACK" number that was already accepted.

## Solution

This solution requires authentication. Please log in to view the full solution.

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