[strongSwan] Problem initilizig ipsec tunnel

[MIDOL MONNET Philippe]

Hello

I'm not familiar with StrongSwan and I have the following issue when I 
try to establish a tunnel:

With the charon log and a tcpdump I can see that, initialisation and 
authentication seem to be OK:

Send: IKE_SA_INIT Initiator Request
Recv: IKE_SA_INIT Responder Response
Send: IKE_AUTH Initiator Request
Recv: IKE_AUTH Responder Response

Therefore there is INFORMATIONNAL:
Send: INFORMATIONAL Initiator Request
Recv: INFORMATIONAL Responder  Request
Send: INFORMATIONAL Initiator Response
At this moment, distant host redo the request and localhost resend the 
response:
Recv: INFORMATIONAL Responder  Request
Send: INFORMATIONAL Initiator Response
Send: INFORMATIONAL Initiator Request
etc..
and the tunnel can't be used

I don't know what happen, can you help me?

Philippe