I am trying to create a front end back end firewall solution using Pix Version 6.3(5) as my front end and Microsoft ISA server 2004 as my backend. I am trying to pass Microsoft client VPN connections thru the Pix firewall and terminate them on the ISA server. I have added these commands to the Pix.
access-list outside_acl permit tcp any host 64.206.48.XX (external address of Pix)
22.218.0.xx is the "external interface" of the ISA server. With this configuration, inside users can access the internet, but any attempts to create and terminate a external VPN connection receives the error "remote computer did not respond." What do I need to do to pass pptp and l2tp traffic to the ISA server?