You can try Astaro Firewal it includes Ipsec VPN & Pptp Vpn on Linux 2.4 Kernal. Its a German Product. For more details u can go on www.astaro.com
Rgds
Girish
On Sat, 15 Dec 2001 Philip S Tellis wrote :
Mr. Ambrish Kumar took the next lecture on IPSec, touching on implementations in windows and linux. There were some doubts as to whether the linux kernel has built in IPSec compatibility or if it requires a recompile. Maybe someone on the list can shed some light on this.
No.Current Linux kernel does not have built in IPSec compatibility,because of the US regulation(NSA can decrypt upto only 64-bit encryption).IPSec allows much better and easy encryption than anybody can decrypt.
Some Distrubutions made outside the US like Polish distribution does provide inbuilt IPSec.
I have recompiled the Linux(2.4.12) with Freeswan-IPSec(1.91) and currently using it with 2048-bit RSA encryption for my VPN network.It gives me descent(and the most secure) performance over the cable connection.
See follwing site for more info. http://www.freeswan.org/