> Source: [sk183042](https://support.checkpoint.com/results/sk/sk183042)

# sk183042 - Security Gateway does not drop packets with invalid TCP checksum

| Property | Value |
|----------|-------|
| Solution ID | sk183042 |
| Date Created | 2025-01-21 |
| Last Modified | 2025-12-08 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82, R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * Security Gateway does not drop packets with invalid TCP checksum.

* Kernel debug ("`fw ctl debug -m fw + drop conn vm`") on the Security Gateway shows that no streaming was assigned to the connection (no "`glue_conn`" found for PSL):

  `;Before VM: <dir 0, xxx:xxx -> xxx:xxx IPP 6> (len=xxx) TCP flags=0x2 (SYN), seq=xxx, ack=0, data end=xxx (ifn=xxx) (first seen) (looked up) ;`

  `;cphwd_pslglue_prepare_offload: no glue_conn found;`
* The command "`fw_mux all`" on the Security Gateway does not show the TCP connection that had to be dropped.

## Cause

The connection does not go through PSL (Passive Streaming Layer), where TCP checksum validation occurs.

## Solution

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

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