[strongSwan] How to disable NAT traversal with strongSwan VPN client app (on android device)?

[Tobias Brunner]

Hi Chinmaya,

> I am using the strongSwan VPN client app (as an IKEv2 initiator) in my
> android device. How can I disable NAT feature? Because by default, it
> sends IKE_AUTH request and data traffic in UDP encapsulated packet which
> I do not want.

You can't.  The app uses the VpnService API and has limited privileges
so it can't send ESP packets directly (as that would require a RAW
socket, which is only possible in root/CAP_NET_RAW processes).  That's
why UDP encapsulation is enforced and can't be disabled.

Regards,
Tobias