[Swan] Windows 10 client to libreswan VPN server: CHILD SA: no local proposal matches remote proposals

[Paul Wouters]

On Wed, 5 Jan 2022, Mirsad Goran Todorovac wrote:

> If I am allowed, I could also assert that I have been positively surprised by 
> the positive change in speed with IKEv2 VPN: while IKEv1 L2TP over IPSec 
> scored about 50 Mbps download on our server, the IKEv2 showed 138 Mbps in 
> Ookla speedtest benchmark :) , over the Faculty's 1 Gbps link and my 150 Mbps 
> home connection.

That's because most likely your l2tp layer went through userland xl2tpd.
it can be configured to use kernel l2tp.ko but that usually has issues.
So yes, I'm not surprised :)

Paul