Forced to upgrade to 2820s and now cannot get lan to lan to work with IPSec Tunnel and L2TP. PPTP is fine.
Copied settings from the 2600s but the VPN connection (not PPTP) fails immediately with the VPN log saying:
Dialing Node2 (xxxxxxxxx) : aaa.bbb.ccc.79
Initiating IKE Main Mode to aaa.bbb.ccc.79
NAT-Traversal: Using RFC 3947, no NAT detected