> Source: [sk122438](https://support.checkpoint.com/results/sk/sk122438)

# sk122438 - Security Gateway accepts another Diffie-Hellman group then what is configured

| Property | Value |
|----------|-------|
| Solution ID | sk122438 |
| Date Created | 2018-01-18 |
| Last Modified | 2020-08-27 |
| Technical Level | Advanced |

## Symptoms

- * When the VPN peer is initiating IKE negotiation with Security Gateway, and is sending another Diffie-Hellman group then what is configured in the VPN community, the Security Gateway accepts it, and later the VPN traffic is dropped.
* Packets are dropped on proposal unmatched, although the VPN tunnel is established.

## Cause

Configuration mismatch - Perfect Forward Secrecy was configured on the Security Gateway, but not on the VPN peer.

## Solution

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