IKEv2
    
  
    
  
| Where
                                                  Can I Use This? | What
                                                  Do I Need? | 
|---|
    
  
 
  
An IPSec VPN gateway uses IKEv1 or 
IKEv2 to negotiate the
                              IKE security association (SA) and IPSec tunnel. Palo Alto Networks
                              IKEv2 implementation is based on 
RFC 7295.
Unlike IKEv1, which uses Phase 1 SA and Phase 2 SA, IKEv2 uses a child SA for
                              Encapsulating Security Payload (ESP) or Authentication Header (AH),
                              which is set up with an IKE SA.
NAT traversal (NAT-T) must be enabled on both gateways if you have NAT
                              occurring on a device that sits between the two gateways. A gateway
                              can see only the public (globally routable) IP address of the NAT
                              device. 
IKEv2 provides the following benefits over IKEv1:
- Tunnel endpoints exchange fewer messages to establish a
                                                  tunnel. IKEv2 uses four messages; IKEv1 uses
                                                  either nine messages (in main mode) or six
                                                  messages (in aggressive mode). 
- Built-in NAT-T functionality improves compatibility
                                                  between vendors. 
- Built-in health check automatically reestablishes a
                                                  tunnel if it goes down. The liveness check
                                                  replaces the Dead Peer Detection used in
                                                  IKEv1. 
- Supports traffic selectors (one per exchange). The
                                                  traffic selectors are used in IKE negotiations to
                                                  control what traffic can access the tunnel. 
- Supports Hash and URL certificate exchange to reduce
                                                  fragmentation. 
- Resiliency against DoS attacks with improved peer
                                                  validation. An excessive number of half-open SAs
                                                  can trigger cookie validation. 
Familiarize yourself with the IKEv2 basic concepts before configuring
                              IKEv2.
After you 
Set Up an IKE Gateway, if you chose IKEv2, perform the following optional tasks related
                              to IKEv2 as required by your environment: