Translations:IPsec L2TP VPN server/181/en

This line is for Windows's benefit. Without it, (at least as of Windows 10) Windows will send EAP probes, which pppd rejects, but Windows will insist, rather then fall back. Manual configuration of the VPN connection will be for Windows to use MSCHAPv2 instead of EAP. By limiting Windows's choice, it will work "out of the box".