Setting up an L2TP VPN server on Synology DiskStation, forwarded ports 500,4500,1701 but the handshake fails for an obscure reason; something like “fatal payload-malformed notify message, phase 1 should be deleted.” What do to? Check the PSK length. It shall not be longer than 64 characters. The UI will accept longer string, however, doing so will result in failures setting up the tunnel.

Yep. That was the whole post. We don’t publish clickbait here on the Trinkets blog.