> Source: [sk1000038](https://support.checkpoint.com/results/sk/sk1000038)

# sk1000038 - VPN traffic is dropped after upgrading a Security Gateway/ ClusterXL with "tunnel is accelerated but packet was not decrypted by SecureXL"

| Property | Value |
|----------|-------|
| Solution ID | sk1000038 |
| Date Created | 2026-08-24 |
| Last Modified | 2026-08-25 |
| Technical Level | General |
| Products | Check Point Firewall |
| Versions | R82.20 |
| OS | Gaia |

## Symptoms

- * After upgrading a Security Gateway/ClusterXL to R82 or higher, traffic does not pass through VPN tunnels.

* The Expert command "`vpn tu tlist`" shows that the tunnels are still up.

* Kernel debug with "`fw ctl zdebug + drop`" shows that VPN traffic is dropped with an error:

  "`tunnel is accelerated but packet was not decrypted by SecureXL`"
* The "`vpn accel stat`" command indicates that VPN acceleration was disabled before the upgrade.

* This parameter is configured in *$FWDIR/boot/modules/fwkern.conf* :  
  `vpn_accel=0`

## Cause

Starting in R82, VPN tunnel acceleration is always enabled (see [sk151114](https://support.checkpoint.com/results/sk/sk151114)).  

When the `vpn_accel=0` parameter remains configured in*$FWDIR/boot/modules/fwkern.conf*, it conflicts with the mandatory VPN acceleration behavior in R82 and higher versions. This configuration mismatch causes VPN traffic to be dropped.

## Solution

1. Remove this line from *$FWDIR/boot/modules/fwkern.conf*:

   vpn_accel=0
2. Reboot the Security Gateway.

3. Make sure that VPN traffic passes successfully through the VPN tunnels after the reboot.

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