What is causing the problem?

In the exhibit, a site-to-site IPSec tunnel between the chassis cluster and the remote SRX240 device will not establish. The chassis cluster and the remote SRX240 device are using their loopback interfaces tor IPSec tunnel termination.

What is causing the problem?

A.
Site-to-site IPSec VPNs are not supported on a chassis cluster; a GRE tunnel must be used instead.

B.
Loopback interface IPSec tunnel termination is not supported on high-end SRX Series chassis clusters; use the reth0 interface instead.

C.
Site-to-site IPSec VPNs between high-end SRX Series chassis clusters and branch SRX devices are not supported. The SRX240 device must be replaced with a high-end SRX device

D.
Loopback interface IPSec tunnel termination within a chassis cluster must have PFS enabled Configure PFS on both ends of the IPSec tunnel.