FreeBSD <-> Windows XP IPSec Phase 1 Timeout

[Arcadiy Ivanov]

Dear everybody,

I have a following problem which you might help me solve. I'm running a 
FreeBSD 6.0 box as a gateway with Windows XP road warrior clients VPNing in. 
In order to setup secure access I want to use IPSec for traffic encryption 
with the plain-text PPTP for tunneling. Windows XP IPSec policy is 
configured to ESP everything coming in and out of TCP port 1723 and GRE and 
same stands for FreeBSD box. Now here is a problem. Upon initiating PPTP 
dial-up connection from XP the IPSec negotiations start normally, both 
client and server agree on encryption & hashing standards successfully. But 
as soon as they do agree, all communications timeout. Tcpdump on FreeBSD box 
and Etherpeek on Windows should the IPSec packets being delivered to both 
machines, but both client and server behave as if packets were not delivered 
at all and obviously timeout. I do have PF firewall on the gateway but the 
result is the same for firewall being off or on or even not loaded into 
kernel. I have used racoon, isakmp and ipsec-tools racoon and the results 
are EXACTLY the same up to the corresponding lines in the logs - as soon as 
encryption policies are successfully negotiated and both clients switch to 
secure communication mode they lose sight of each other and both timeout. I 
of course understand that the logs are necessary and I'm ready to provide 
them if anybody is interested to help me solve the problem, but I'm hoping 
that somebody had this problem and knows the solutions off the top of 
his/her head.

Thanks a lot,
Arcadiy