The below topology is running DMVPN Phase 3. R1-3 are spokes and R5 is the hub. Currently the routers are all running IPSEC via IKEv1 and we’re going to change this to IKEv2.

  • IKEv1 vs. IKEv2 (out of scope for CCIE)
    • IKEv2 can use asymmetric authentication.
      • ie. one side running PSK and other running PKI.
    • IKEv1 has to be the same on both.

By removing the line ‘no tunnel protection ipsec profile vpnprof we’re able to remove IPSEC IKEv1 from each tunnel interface. The IKEv1 configuration will still be on the box but not applied to anything.

The configuration for IKEv2 will be the following:

crypto ipsec transform-set cisco-ts esp-aes esp-sha256-hmac

mode transport

crypto ikev2 keyring cisco-ikev2-keyring

peer dmvpn-node

description symmetric pre-shared key for the hub/spoke

address 0.0.0.0 0.0.0.0

pre-shared-key cisco123

crypto ikev2 profile cisco-ikev2-profile

 match identity remote any

 authentication remote pre-share

 authentication local pre-share

 keyring local cisco-ikev2-keyring

authentication local pre-share

match address local 0.0.0.0

crypto ipsec profile cisco-ipsec-ikev2

set transform-set cisco-ts

set ikev2-profile cisco-ikev2-profile

int tunnel 0

tunnel protection ipsec profile cisco-ipsec-ikev2

NOTE – Transport vs. Tunnel mode:

  • Transport
    • Encrypts only the payload of packets, not the header.
  • Tunnel
    • Encrypts the entire payload and header.
    • Ultimately more secure.

After these lines are configured on ALL routers, the VPN tunnels and BGP adjacencies move into the Up state.

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