Hi Yogesh, > No it is not strongswan on peer end. I am using third party VPN.
Which probably means the peer sends an invalid TS payload. > So is the IKE_AUTH packet size is fixed to 204 bytes for PSK mode and > anything exceeding that can be Invalid length. There are no fixed sizes for any messages or modes. You have to look closely at the structure of the receive message and the contained payloads (either increase the log level for enc to 3 or export the IKE keys and use Wireshark to analyze the IKE_AUTH message). Regards, Tobias