The following description of the AH protocol in IPSec VPN, which one is wrong?

The firewall security group supports up to three levels of nesting, namely parent security group, security group, and child security group.

Information security prevention technologies include : data encryption, identity authentication, intrusion prevention, anti-virus, etc.

Please match the following different NAT technologies with the corresponding application scenarios.

() mode: two devices, one master and one backup. Under normal circumstances, service traffic is handled by the active device. When the active device fails, the backup device takes over the active device to process business traffic to ensure uninterrupted services.