Yeah...I'd agree with the previous poster. Your ISP is blocking IPSEC because they dont want it on their network, and if 'no vpn' is stated in their Acceptable Uses and TOS they have every right to block it, and they have every right to terminate your buddy's service if they detect him trying to setup and use some sort of VPN tunnel. If this is the case, your solution is to either switch ISP's to one that doesnt block VPN (RoadRunner, TXU, Alltel, and SBC are a few that come to mind), or setup a Secure FTP server on whatever PC your buddy wants to VPN to and access files from, but if your ISP blocks VPN's they probably block servers too.
If your buddy loves this ISP so much and doesnt want to switch perhaps he should give up trying to get around their restrictions before they terminate his service completely.
If your buddy loves this ISP so much and doesnt want to switch perhaps he should give up trying to get around their restrictions before they terminate his service completely.