# Site to Site VPN traffic in Load Sharing cluster is not synchronized across members and dropped

## Product
**Site-to-Site VPN**  
## Version  
**R80.40 (EOS), R81 (EOS), R81.10 (EOS), R81.20**  
## OS  
**Gaia**  
## Platform  
**All**  
## Last Modified  
**2023-08-14**

## Symptoms
- In a Site to Site VPN, when one of the sites is a cluster in Load Sharing mode, packets are dropped with " _vpn_decrypt_verify Reason: CONN_ENC_NO_ENTRY[_SR] with packet reversed to the original direction of the connection_"

## Cause
When one of the sites is a cluster in Load Sharing mode, both peers open renegotiation simultaneously, and each side uses different tunnel for encryption. This can be seen in the _Ike.elg_ file: the Security Gateway and the peer send renegotiations at the same time.

It causes incorrect destination member calculation for asymmetric connection and leads to traffic drops.

## Solution
This problem was fixed. The fix is included in:
- [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 26
- [Jumbo Hotfix Accumulator for R81.10](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/Default.htm) starting from Take 95
- [Jumbo Hotfix Accumulator for R81](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81/Default.htm) starting from Take 87

Install this Take on every member of the VPN that is a cluster.

**To enable the fix**, enable the kernel parameter on each Security Gateway:
```
[Expert@HostName]# ckp_regedit -a SOFTWARE/CheckPoint/VPN1 ikev1_initiator_opens_reneg -n 1
```
To apply the change, kill the VPND/IKED processes.

**To disable the fix**, run on each Security Gateway:
```
[Expert@HostName]# ckp_regedit -d SOFTWARE/CheckPoint/VPN1 ikev1_initiator_opens_reneg
```
To apply the change, kill the VPND/IKED processes.

If you choose not to upgrade, Check Point can supply a **Hotfix**. [Contact Check Point Support](https://www.checkpoint.com/support-services/contact-support/) to get a Hotfix for this issue.

A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.

For faster resolution and verification, please collect [CPinfo files](http://supportcontent.checkpoint.com/solutions?id=sk92739) from the Security Management Server and Security Gateways involved in the case.

**Hotfix installation instructions:**  
Refer to [sk168597 - How to install a Hotfix](https://support.checkpoint.com/results/sk/sk168597).

**If the Hotfix cannot be installed**, the kernel parameter can be set to force FnA for encrypted traffic:
```
[Expert@HostName]# fw ctl set int try_prevent_fna_for_vpn 0
```
Note: This can introduce traffic slowness.

## Article Properties
**Access Level:** General  
**Status:** Approved  
**Date Created:** 2023-04-30  
**Last Modified:** 2023-08-14