> Source: [sk165998](https://support.checkpoint.com/results/sk/sk165998)

# sk165998 - VPN traffic dropped with "dropped by vpn_ipsec_decrypt Reason: decryption failure: tunnel is accelerated but packet was not decrypted by SecureXL"

| Property | Value |
|----------|-------|
| Solution ID | sk165998 |
| Date Created | 2020-04-03 |
| Last Modified | 2020-11-12 |
| Technical Level | Advanced |
| OS | Gaia |

## Symptoms

- * Tunnel is up, but site-to-site VPN traffic is dropped with "dropped by vpn_ipsec_decrypt Reason: decryption failure: tunnel is accelerated but packet was not decrypted by SecureXL;"
* Turning off VPN acceleration with "vpn accel off" resolves the issue.
* Output of "ip route get" of the destination address is using a link, on which the VPN is not terminated.
* reply_from_same_IP is set to "true"
* SecureXL kernel debug for interesting VPN traffic shows "localip error" print: \[cpu_0\];\[SIM-206960861\];vpn_decrypt: connection localip error; \[cpu_0\];\[SIM-206960861\];sim_db_get_any_conn: conn not found (vsid 0), ret -1;
* External interface has an alias IP, and the relevant external IP is defined as alias IP.

## Cause

Different interface for processing the VPN traffic than where the VPN is terminated.

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## Solution

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