> Source: [sk122072](https://support.checkpoint.com/results/sk/sk122072)

# sk122072 - 'TCP out of Sequence' logs in SmartConsole

| Property | Value |
|----------|-------|
| Solution ID | sk122072 |
| Date Created | 2018-01-09 |
| Last Modified | 2025-02-17 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * "TCP out Of Sequence" logs from a Security Gateway in SmartConsole / SmartView.

* In traffic capture on a Security Gateway, the packets that create the logs are "TCP Keep-Alive".

## Cause

A "TCP Keep-Alive" packet is sent with a sequence number which is one less than the sequence number the receiver is expecting, because the receiver has already acknowledged the sequence number of the Keep-Alive. This causes the Security Gateway to detect the packets as "TCP out of Sequence".

Example of "TCP Keep-Alive" packet in WireShark:

![](https://sc1.checkpoint.com/sc/SolutionsStatics/NEW_SK_NOID1514116533572/Capture1712240513.PNG)

## Solution

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

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