We are trying to establish vpn connection using cisco vpn client on laptop to a vpn concentrator in a remote office. All network devices are in the same private network. There is a Cisco ASA 5505 firewall sitting between VPN client and VPN Concentrator. IPSec over TCP & IPSec over UDP works fine. But plain IPsec will not work. We will be able to establish connection with plain IPSec but can't access resources behind the VPN concentrator. I am attaching the config Cisco ASA firewall for your reference. Please let me know what I am missing.