I have configured an ipsec vpn tunnel using a Netgear FVS 318 and the Netgear Prosafe vpn client software v.10.1.1. I have tested the connection from my home using a cable/dsl modem and Linksys router using ipsec passthrough and all is good to go. I am able to browse and ping the remote internal network. The issue arises when I have the client's software developer attempt to connect remotely. The developer is also using the Netgear Prosafe software with identical configurations (different IP's and connection name) as the working connection in my home. When he attempts to connect, the vpn tunnel is established , but no traffic appears to be traversing the link once the connection is made. He is connected via ISDN Modem (TA) directly connected to the ISP's Cisco Router/Pix which performs the NAT translation. I have quickly tried static routes on his PC (WinXP Pro) in an attempt to force the traffic thru the tunnel. This was not successful, and now I am looking @ the possibility of ports being blocked by his ISDN provider. According to the logs of the Netgear router, it seems to be accepting IKE traffic on port 500/UDP, but I am unable to see any other actiuvity. What other ports need to be opened to pass ipsec traffic? and am I headed in the right direction on this as my client needs this up and running ASAP for application maintenance. All replies are appreciated, and thanks in advance. Please let me know if you need any additional information.