I have a Cisco 1721 router behind my Cisco Pix 515 firewall that is to be used for VPN connectivity to another office. The only instructions I have been given are access list requirements to allow IPSEC tunnel traffic from the VPN router through my firewall. I've added the access list requirements but I cannot connect to the other office. I have searched through configs and have seen entries to configure IPSEC but I am not sure of what I need for a basic configuration. Any help would be greatly appreciated.